SES Instruments Pvt. Ltd.

We offer Temperature Control System use full for control labs.This experiment has been designed to expose the students to a practical control system, its various stages for control, and the tuning of a PID controller. The process consists of a small and fast responding oven which can be controlled in the temperature range from ambient to about 90°C. Temperature readings may be taken manually on a 3½ digit meter, mounted on the main unit, at regular intervals. The oven is connected to the main unit through a four pin connector, two for the sensor input and the others for controller output to the heater.

>> Highlights:-

• Fast compact oven upto 90°C
• Forced cooling option
• Variety of control actions
• Digital temperature readout
• Built-in timer, 0-9999 sec.
• Solid state temperature sensor

>> Experiments:-

• Identification of the oven parameters
• Study of ON-OFF temperature control (with adjustable relay characteristics)
• Study of P, PI, PD and PID controls having adjustable coefficients

>> Features and Specifications:-

• Temperature controller with facilities for P, I, D and relay control blocks
• Operating temperature: Ambient to 90°C
• Separate controls for P, I, D channel gains
• Two settings for relay hysteresis
• Fast 25W oven fitted with IC temperature sensor
• Forced cooling option to ready oven for next experiment
• Digital display of set and measured temperature on a 3½ digit built-in DVM
• Buffered output for recorder
• IC regulation in controller circuit power supplies
• 220V±10%, 50Hz mains operation
• Supporting literature and patch cords included
• No accessories required

We offer Study of P-N Junctions, this is an advanced level experiment to be performed on commercially available diodes viz. germanium or silicon diodes, various types of LED’s and also on the base-emitter/ collector-base junctions of a transistor. The results of the experiments not only give the device characteristics but also provide an insight into the properties of the materials used in the fabrication of the junction. In the set-up, all the necessary instrumentation is integrated as a result of which a minimum of external connections need to be made by the user. A CRO is the only accessory that is required.
The following studies can be carried out.
(i) Reverse saturation current l0 and material constant h
(ii) Temperature coefficient of junction voltage dV/dt
(iii) Energy band-gap VG0
(iv) Junction capacitance
The experimental set-up consists of the following:
(1) Study of P-N Junctions, Model PN-1
(a) 3½ digit DPM for current/ temperature measurement.
(b) 3½ digit DPM for bias voltage/ junction voltage measurements.
(c) To connect the diode – one for experiment 1 & 2 and other for experiment 3.
(d) Two fixed frequency oscillators (5KHz & 20KHz) with the same output (200mV).
(2) Fast temperature controlled oven with sensor, PNO-01
(3) PNJ-Sample
(a) Transistor BC109 (base-emitter)-Si
(b) Transistor AC128 (base-emitter)-Ge
(c) Diode: IN 5408/IN 4002-Si
The unit is supplied complete with a detailed instruction manual. Sufficient theoretical description is included for a proper understanding. This is followed by a step-by-step procedure and a typical set of readings and results. The set-up is complete in all respect, except a CRO.

We offer Potentiometric Error Detector useful for control labs. All feedback control systems operate from the error signal which is generated by a comparison of the reference and the output. Error detectors perform the crucial task of comparing the reference and output signals. The present set-up is designed to study the important characteristics of a 2-potentiometer angular position error detector. These include
(i) linearity,
(ii) sensitivity and
(iii) maximum angle of rotation.
Good quality wire wound servo potentiometers with full 360° rotation have been used for this purpose. Accurately marked dials with least count of 1° are fixed on the shafts for position indication. The error voltage is read on a built-in 3½ digit DVM. An I.C. regulated internal reference voltage is available for d.c. studies. When used with an a.c. reference, the unit also demonstrates the phase reversal of the error signal which is important in applications involving a 2-phase servomotor as actuator.
Highlights

• High quality servo potentiometers
• 360° Mechanical, 355° Electrical span
• DC and AC operation
• 3½ Digital Panel Meter for all measurements

Experiments

• Linearity study of the error detector
• Determination of error detector gain
• Use of a.c. supply for the error detector-introduction to the phase reversal of error signal

Features and Specifications

• High quality servo-potentiometers of 360° shaft rotation
• Requires an external CRO for a.c. studies
• Built-in signal and power sources
• 3½ digit DVM for measurements

The experiment is complete in all respect, except a CRO.

We offer Light Intensity Control System useful for control labs. The light intensity control system is designed to bring out the basic features of closed loop systems in the form of a laboratory experiment. The light panel comprises of a number of filament lamps which get power from amplifier. Average intensity of the panel is sensed by a light sensor and a suitable voltage level is produced. Error detector, reference input and error amplifier are of standard configurations found in any linear control system. In addition to the above, the light panel also contains a few uncontrolled lamps which may be used as disturbance source. Further a square wave signal is available for dynamic response studies.
Highlights

• Feedback control of light intensity
• Study of inherent non-linearties-sensor, lamps
• PI control
• Dynamic response displays

Experiments

• Characterization of light panel and light sensor blocks
• Study of a practical single loop feedback control system which includes:

• Disturbance study
• Error monitoring

• Performance improvement through P-I control
• Evaluation of dynamic behavior

Features and Specifications

• Built-in 3½ digit DVM
• Built-in IC regulated power supplies
• Literature and patch cords included
• Seven lamps 6V/300mA
• 5Hz square wave and triangular wave for dynamic response study

The experiment is complete in all respect.

We offer Function Generator, FG-01. This is an economically priced signal source for a wide variety of applications in electronics, communication and control systems laboratory. The IC used is a high frequency function generator that produces low distortion sine, triangular, sawtooth and square waveforms from frequencies less than a Hz. To 20MHz. A minimal of external components are needed which make the unit very reliable and robust. The desired output waveform is selected by logic control and may therefore be done electronically as well.
Basic principal of function generation used is the relaxation oscillation with periodic charging and discharging of a capacitor through constant current source. The charging/discharging currents are accurately controllable and the associated circuits support high frequencies very well. A sine shaping circuit coverts the triangular waveform to sine wave of constant amplitude. The sine wave is useful for frequency response studies of amplifiers, filters and other electrical systems, while the square wave finds applications in transient response studies. Triangular wave is a standard input signal for the study of steady state error in feedback control systems. All power supplies are IC regulated.
Features
• 4-digit counter based frequency display-Maximum error ONE LSB
• Square, sine and triangular output upto 2 MHz.
• IC based circuit - high stability, low distortion
• Regulated power supply
Specifications
Waveforms: Square/ Sine/ Triangular (switch selectable)
Frequency: 10 Hz - 2 MHz in five ranges
Amplitude: Square 0-3V (p-p), Triangular 0-3V (p-p), Sine 0-3V (p-p)
Output Impedance: 50Ω
Frequency Readout: 4-digit, counter based, automatic decimal point
Power Supply: 220V±10%, 50Hz

We offer Regulated Power Supply, PS-12, it is general purpose power supply consists of four independent fixed voltage regulated sources viz. +12 V, -12 V, +5 V and -5 V referred to a common ground. The current rating for each is specified at 300 mA, although it is possible to exceed this limit safely when all four sources are not operating simultaneously.
The compact power supply unit is well suited for any general laboratory which uses linear and digital circuits and IC's. At the same time the excellent performance of the 3-terminal regulators enables the supplies to be used equally satisfactorily for sophisticated instrumentation applications. The built-in protection of the regulator in the form of over current and safe area shutdown ensure continued fault free operation of the unit without any maintenance.
Specifications
Output voltage: + 12 V, - 12 V, + 5 V, - 5 V fixed
Current: 300 mA (each supply)
Line Regulation: ± 0.05 % for 10 % variation of mains voltage.
Load Regulation: ± 0.1% for a full load of 300 mA
Protection: Thermal and over-current.
Dimensions: 210 m.m. X 180 m.m. X 100 m.m.
Weight: 2.25 Kg

We offer a classroom experiment for measurement of Resistivity of Semiconductor by Four Probe Method at different temperatures and determination of the band-gap The Four Probe Method is one of the standard and most widely used method for the measurement of resistivity. In its useful form, the four probes are collinear.

Description of the experimental set-up:
1. Probes Arrangement, FPA-03: It has four individually spring loaded probes. The probes are collinear and equally spaced. The probes are mounted in a teflon bush, which ensure a good electrical insulation between the probes.
2. Smaple: Germanium crystal in the form of a chip.
3. Oven, FPO-03: This is high quality temperature controlled oven suitable for Four Probe Set-up. The oven has been designed for fast heating and cooling rates, which enhances the effectiveness of the controller.
4. Four Probe Set-Up, DFP-03: The set-up consists of three units housed in the same cabinet.
(i) Oven Controller
(ii) Multi range Digital Voltmeter
(iii) Constant Current GeneratorThe experimental set-up is complete in all respect.

We offer Four Probe Method, DFP-02it is one of the standard and most widely used method for the measurement of resistivity of semiconductors. The experimental arrangement is illustrated. In its useful form, the four probes are collinear. The error due to contact resistance, which is specially serious in the electrical measurement on semiconductors, is avoided by the use of two extra contacts (probes) between the current contacts.
In this arrangement the contact resistance may all be high compare to the sample resistance, but as long as the resistance of the sample and contact resistances are small compared with the effective resistance of the voltage measuring device (potentiometer, electrometer or electronic voltmeter), the measured value will remain unaffected. Because of pressure contacts, the arrangement is also specially useful for quick measurement on different samples or sampling different parts of the same sample.

>> The experiment consists of the following:

(i). Four Probes Arrangement, FPA-02:
It has four individually spring loaded probes. The probes are collinear and equally spaced. The probes are mounted in a teflon bush, which ensure a good electrical insulation between the probes.

(ii). Sample: Germanium crystal in the form of a chip

(iii). Oven: It is a small oven for the variation of temperature of the crystal from the room temperature to about 200°C (max.)

(iv). Thermometer DFP 02-THR (0-150°C)
(v). Four Probe Set-up, DFP-02
The set-up consists of three units in the same cabinet.
(a) Multirange Digital Voltmeter
(b) Constant Current Generator
(c) Oven Power Supply: Built-in for the above oven.
Typical results obtained from this set-up are shown in the datasheet.
The experimental set-up is complete in all respect.

We offer precision Digital Microvoltmeter very useful in general laboratory and R&D labs. It is a very versatile multipurpose instrument for very low dc voltage measurement at very high impedance.
Features

• Very low temperature drift
• Low dc input bias current-10pA
• Measures voltage down to 1mV
• Recorder facility (optional)

Specifications
Range: 1mV, 10mV, 100mV, 1V & 10V with 100% over-ranging.
Resolution: 1μV.
Accuracy: ±0.2%.
Stability: Within ±1 digit.
Input Impedance: >1000MΩ (10MΩ on 10V range).
Display: 3½ digit, 7 segment LED with auto .polarity and decimal indication

Relay Control System, RCS-01:
We offer Relay Control System use full for control labs. In the present unit a simulated second order system is controlled by an electronic relay. Apart from a study of the relay characteristics the experiment introduces the concept of Describing Function. Finally the phase plane method of analysis is covered in detail where the switching trajectories can be displayed on an X-Y oscilloscope.
Highlights

• System with electronic relay
• Adjustable hysteresis and dead zone
• Display phase plane diagram on CRO
• Stability study by describing function method

Experiments

• Study of the relay characteristics and display of the same on CRO for different values of hysteresis and dead zones.
• Study of the effect of hysteresis on system stability. Graphical analysis to predict sustained oscillations.
• Phase plane analysis of relay control system for various values of Hysteresis and Dead Zones. View the trajectory for different hysteresis and dead zone.

Features and Specifications

• Simulated electronic relay using high speed IC’s
• Simulated 2nd order linear plant. Facility for displaying x and x. signals
• Dead zone variable from 0-600mV
• Hysteresis variable from 0-500mV
• Built-in signal sources – Sine and

Square Amplitude: 0-1V (min.)
Variable Frequency: 10, 20, 40, 80, 100, 200, 400, 800 and 1000Hz

• IC regulated internal power supplies
• Literature and patch cords included
• Accessory - a dual beam CRO

The experiment is complete in all respect, except a CRO.

We offer Study of Multivibrators, MV-01, this experiment consists of the following:

1. Free Running vibrator
2. Univibrator
3. Bistable Multivibrators
4. Regulated Power Supply

The free running multivibrator also serve as a pulse generator for the study of bistable multivibrator and univibrator.
The set-up is so designed that no high voltage is exposed and hence safe in handling by the students.

We offer Digital Gauss meter, DGM-204 suitable for magnetic field measurement from 0.1 gauss to 40KG. Easy interchangeability of probe enables both axial and transverse field measurement with same unit.
Features

• Measures down to 0.1G
• Excellent Linearity
• Excellent Stability
• Interchangeable Hall Probes

Specifications
Range: 0-200G, 0-2KG, 0-20KG and 0-40KG.
Accuracy: ±0.5%.
Resolution: 0.1 gauss at 200G range.
Display: 3½ digit, 7 segment LED with auto polarity and overflow.
Transducer: Hall Probe (InAs).
Special Feature: Indicate the direction of the magnetic field.

We offer Study of a Solid State Power Supply, SSPS-01, following studies can be carried out with this set-up.
(1) Study of rectification.
(a) Full wave rectification
(b) Half wave rectification.
(2) Study of ac component (Ripples):
(a) Efficiency of various type of filters, T type etc
(b) The effect of load
(c) The effect on regulation
(3) Regulation characteristics:
(a) The effect of load on regulation.
(b) The effect of change in main’s voltage.
>> Accessories Required :
(i) Multimeter
(ii) Oscilloscope
The set-up is so designed that no high voltage is exposed and hence safe in handling by the students.

We offer Study of Digital-to-Analog Converter, DTA-01 useful for control labs. Measurement of the speed of a rotating shaft is a common requirement in many industrial and laboratory applications. Stroboscope, is a convenient-to-use, direct reading speed measuring instrument. A highly stable function generator IC based circuit provides the basic variable frequency timing pulses.
These are read on an IC based LCD/LED counters with direct speed display in rpm. The flasher unit generates the high intensity flashes at a suitably scaled rate directed towards the rotating shaft. Precision potentiometer's makes the task of speed setting very precise. The portable model, fitted into a light weight and strong plastic body is more suited for industrial / class room environment.

>> Highlights:-

• Basic 4-bit weighted resistance
• 4-bit R-2R network module
• 10-bit IC Type AD7533 with mechanical switches
• MIcroprocessor interfaced 10-bit converter

>> Experiments:-

• Study of the circuit diagram and performance of a 4-bit weighted resistance type D/A converter. The digital inputs are to be given by operating four mechanical switches.
• The above experiment is conducted on a 4-bit discrete component R-2R network based unit.
• Manual operation of a 10-bit IC D/A converter type AD7533 through 10 mechanical switches.
• Operation of the IC based circuit through the microprocessor kit provided. Some typical waveform generation exercises are suggested and solutions are provided. More problems can be attempted by the student with help from his supervisor.

>> Features and Specifications:-

• Advanced Experiments-arbitrary waveform generation
• Panel Meter for all measurements
• A measuring CRO is needed for viewing the waves forms

The experiment is complete in all respect, except a CRO.

Temperature Control System, TCS-01:
We offer Temperature Control System use full for control labs.This experiment has been designed to expose the students to a practical control system, its various stages for control, and the tuning of a PID controller. The process consists of a small and fast responding oven which can be controlled in the temperature range from ambient to about 90°C. Temperature readings may be taken manually on a 3½ digit meter, mounted on the main unit, at regular intervals. The oven is connected to the main unit through a four pin connector, two for the sensor input and the others for controller output to the heater. The main unit has provisions for configuring any type of controller such as P, PI, PD, PID or ON-OFF, and has potentiometer controls for PID coefficient settings.
Highlights

• Fast compact oven upto 90°C
• Variety of control actions
• Digital temperature readout
• Solid state temperature sensor

Experiments

• Identification of the oven parameters
• Study of ON-OFF temperature control (with adjustable relay characteristics)
• Study of P, PI, PD and PID controls having adjustable coefficients

Features and Specifications

• Temperature controller with facilities for P, I, D and relay control blocks
• Operating temperature: Ambient to 90°C
• Separate controls for P, I, D channel gains
• Two settings for relay hysteresis
• Fast 25W oven fitted with IC temperature sensor
• Digital display of set and measured temperature on a 3½ digit built-in DVM
• Buffered output for recorder
• IC regulation in controller circuit power supplies
• 110V±10%, 60Hz mains operation
• Supporting literature and patch cords included
• No accessories required

We offer Study of Dielectric Constant and Curie Temperature of Ferro electric Ceramics. Dielectric or electrical insulating material are understood as the material in which electrostatic field can persist for long times. Layers of such substance are commonly inserted into capacitors to improve their performance, and the term dielectric refers specifically to this application. The present setup demonstrates is useful for students to get first hand experience of this parameter in laboratory environment.
Description of the experimental set-up
1. Probes Arrangement, DEA-01: It has two individually spring loaded probes. The probes arrangement is mounted in a suitable stand, which also holds the sample plate.
2. Sample Barium Titanate (BaTiO₃)
3. Oven, DEO-01: This is a high quality temperature controlled oven. The oven has been designed for fast heating and cooling rates, which enhances the effectiveness of the controller.
4. Main Units: The Set-up consists of two units housed in the same cabinet.
a) Oven Controller Platinum RTD (A class) has been used for sensing the temperature. A Wheatstone bridge and an instrumentation amplifier are used for signal conditioning.
Specifications of the Oven:
Temp. Range: Ambient to 200°C
Resolution: 1°C
Stability: ±0.2°C
Accuracy: ±0.5 (typical)
Sensor: RTD (A class)
Display: 3½ digit, 7 segment LED with autopolarity and decimal indication Power: 150W
b) Digital Capacitance Meter: This a compact direct reading instrument for the measurement of capacitance of the sample.
Specifications
Range: 50-6000pf
Resolution: 1pf
Display: 3½ digit, 7 segment LED with autopolarity and decimal indication.

We offer Digital Control System useful for control lab. In the present unit a second order transfer function, simulated with operational amplifiers and passive components, has been chosen as the process to be controlled. This results in a well behaved and near perfect linear process which gives a highly predictable performance. The digital controller consists of a 8085 based microprocessor kit with analog-to-digital and digital-to-analog interface. Software supplied with the system resides in a 8K EPROM. This consists of P, PI and PID algorithms in which the three gains may be selected out of 16 levels each. Further, the user may write his own programs to implement additional algorithms and study their responses.
Highlights of the equipment:

• Digital Controller implementation on mP-kit
• Simple Op-amp based analog plant
• CRO display of response
• Design and test new algorithms

Experiment:

• Identification of the controlled process
• Study of sampling period variation
• Designing P, PI, PD and PID controllers
• Advanced algorithms implementation

Features and Specifications:

• Second order simulated process (analog process)
• Built-in D/A and A/D circuits (8-bit)
• 8085 based mP kit as digital controller with user software in 8K EPROM
• 16-bit arithmetic for algorithmic calculations.
• Square wave test input (internal)
• 16 built-in levels of P, I and D gains each.
• Complete flexibility for the user to develop own software
• IC regulated internal built-in power supplies
• Detailed literature and patch cords included
• Essential accessory - a CRO

The experiment is complete in all respect.

We offer high quality Traveling Microscope whose bed is of a heavy casting, thoroughly aged and machined, is fitted with leveling screws. On the dovetailed guide ways slide the carriage which can be clamped at any position by means of a thumbscrew. A sliding carriage slides along a gunmetal Vertical pillar fitted on the horizontal carriage. The slow motion guide bars are made of sturdy material and the motion is very smooth. Microscope Tube Inclinable in any angle. True vertical and horizontal positions marked focusing. Guide Ways The guide ways over which slides the carriage is made of gunmetal and this makes the instrument Rust Proof, because this is the part which is directly exposed to the weather. Scales and Verniers Made of lifetime Stainless Steel.
Optics
True achromatic objective with 7.5 cm. focusing distance from object; 10X Rams den Eyepiece with fine cross wire is provided.
Scale
Horizontal scale: 180mm with a screw gauge type motion
Vertical scale: 150mm with a vernier scale
Lateral scale: 60m3 with a vernier scale
Least Count: 0.01mm

We offer Electromagnet, EMU-75 is useful in general laboratory and R&D labs. It has the most widely used 'U' shaped soft iron yoke. The soft iron is of a special quality, structurally uniform, well machined and finished to meet the rigid standards. The pole pieces are made from dead annealed soft iron blocks of the best quality available. They are well shaped, machined and finished. The air-gap is continuously variable up to 75mm with two way knob bed wheel screw adjusting system. Normally flat pole pieces are supplied. Tapered pole pieces can be supplied on special request. The coils are wound on non-magnetic formers with uniform layers of S.E. copper wire. The new and modern design of the coils provides good thermal conductivity characteristics and eliminates troublesome hot spots even at high magnetic fields.

Specifications of EMU-75
Pole Pieces: Φ75mm flat in EMU-75
: Φ75mm tapered to 25mm in EMU-75T
Field: EMU-75: 10.75KG at 10mm air gap
: EMU-75T: 17.5KG at 10mm air gap
Energizing Coils: Two, each having a resistance of approx. 13Ω
Power Requirement
*0-90Vdc, 3A, if coils are connected in series
*0-45Vdc, 6A, if coils are connected in series
Constant Current Power Supply DPS-175 is designed to be used with the Electromagnet, Model: EMU-75 as a constant current power supply to generate magnetic field up to 11KG.

Specifications of DPS-175
Current: 0-3A per coil Smoothly adjustable
Line Regulation: ±0.1% for 10% mains variation
Load Regulation: ±0.1% for load variation from 0 to max.
Display: 3½ digit, 7 segment LED display
Protection: Protected against overload, short circuit and transients caused by the load inductance.
Power: 220V 10%, 50Hz or 110V 10%, 60Hz as required
Weight: 13Kg.

We are offering Franck-Hertz Experiment useful in Physics and Material Science Lab. The Franck Hertz Experiment verify the consideration, Franck and Hertz set out to verify in 1914:
* It is possible to excite atoms by low energy electron bombardment.
* The energy transferred from electrons to the atoms always had discrete values.
* The values so obtained for the energy levels were in agreement with spectroscopic results.
Thus the existence of atomic energy levels put forward by Bohr can be proved directly. It is a very important experiment and can be performed in any college or University level laboratory.
The Experiment is consists of the following:
* Argon filled tetrode
* Filament Power Supply: 3.6-3.4V continuously variable
* Power Supply for V_G1K: 1.3-5V continuously variable
* Power Supply for V_G2A: 1.3 - 12V continuously variable
* Power Supply for V_G2K: 0 - 95V continuously variable
The instrument can, not only lead to a plot of the amplitude spectrum curve by means of point by point measurement, but also directly display the amplitude spectrum curve on the oscilloscope screen. This instrument can thus be used as a classroom experiment as well as for demonstration to a group of students.
Analysis of Data:
Data obtained for the excitation potential point by point are shown in Fig. 3. The readings are taken for 1V changes on grid 2 (V_G2K). A significant decrease in electron (collector) current is noticed every time the potential on grid 2 is increased by approximately 12V, thereby indicating that energy is transferred from the beam in (bundles) "quanta" of 12eV only. Indeed, a prominent line in the spectrum of argon exists at 1048Å corresponding to eV=11.83.

We have a wide range of experiments/ equipment for Post Graduate and Under Graduate Physics Laboratories.
For Detail datasheet of all our productsplease contact us.

We are offering Digital Nanoammeter, DNM-121, a rugged and low cost instrument, is a product of extensive R&D using high input impedance integrated circuits. It has 4 decade ranges with 100% over-ranging. The unit is suitable for current measurement in the range of 100pA to 200µA. For the ease, readings are directly displayed on a 3½ digit DPM. The instrument is capable of accepting either polarity of the input current.
The very low leakage current of the input stage combined with the high linearity and fast response due to high negative feedback enables accurate and easily reproducible measurements. The instrument uses a FET input operational amplifier in current to voltage converter configuration and offers the very low input bias current, low offset voltage, low drift and noise.
Features

• Measures current down to 100pA
• All solid state and IC design
• Accepts either polarity of input current.

Applications
a. To measure current from photomultiplier tubes, photometer etc.
b. Leakage currents in solid state devices. FET gate and tube grid voltages without loading errors.
c. Current through very high resistance in conjunction with a power supply.
d. Potentials across semiconductors, piezoelectric systems & pH electrodes.
Specifications
Range: 100nA, 1µA, 10µA, 100µA with 100% over-ranging
Accuracy: 0.2% for all ranges.
Resolution: 0.1nA.
Input impedance: 25Ω, 2.5Ω, 0.25Ω, 0.025Ω
Display: 3½ digit, 7 segment LED (12.5mm height) with auto polarity and decimal indication..
Input: Through Amphenol connector.
Power Supply: 220V±10%, 50Hz.
Weight: 2.5Kg.
Dimensions: 240mm X 275mm X 120mm.

We offer Two Probe Set-Up, TPX-01 Method for resistivity measurement of insulators at different temperature. It is one of the standard and most commonly used method for the measurement of resistivity of very high resistivity samples like sheets/films of polymers. The resistivity measurement of such samples is beyond the range of Four Probe Method.

>> The experimental Set-up consists of the following:

1. Two Probes Arrangement, TPA-01
It has two spring load contact probes. These probes move in a pipe and are insulated by Teflon washers. This probes arrangement is mounted in suitable stand, which also hold the sample plate and RTD sensor.

2. PID Controlled Oven, PID-200
This is a high quality temperature controlled oven suitable for Four Probe Set-up. The oven has been designed for fast heating and cooling rates, which enhances the effectiveness of the controller.
Specifications of the Oven
Temperature Range: Ambient to 200°C
Resolution: 0.1°C
Short Range Stability: ±0.2°C
Long Range Stability: ±0.5°C
Measurement Accuracy: ±0.5°C (typical)
Oven: Specially designed for Four Probe Set-Up
Sensor: RTD (A class)
Display: 3½ digit, 7 segment LED
Power: 150W

3. High Voltage Power Supply, EHT-11
4. Digital Picoammeter, DPM-111

The experimental set-up is complete in all respect.

We offer Hall Effect in Metals, , HEM-01. It enables the charge carrier concentration and mobility to be determined by experiment. Direction of the Hall Voltage in silver indicates negative charge carriers, which is in agreement with concepts of the model of the ‘free electron gas‘. Limitations of this model are shown by the so called ‘abnormal Hall Effect’ of tungsten. The experiment carried out under identical conditions for tungsten show the Hall Voltage to have about same magnitude but opposite direction as in silver.
>> The apparatus consists of the following:
a) Hall Probe-Silver (HP-Ag)
Material: Silver Strip (8 x 6 x 0.05 mm)
Contacts: Press type for current, Spring Type for Voltage
Hall Voltage: ~17 μV/10A/10KG
b) Hall Probe-Tungsten (HP-W)
Material: Tungten Strip (8 x 6 x 0.05 mm)
Contacts: Press type for current, Spring Type for Voltage
Hall Voltage: ~15 μV/10A/10KG
c) High Current Power Supply, Model PS-20A
Range: 0-20A continuously variable
Accuracy: ±0.5%
Regulation: ±0.5% for ±10% variation of mains

d) Digital Microvoltmeter, DMV-001

e) Electromagnet, Model EMU-75T
Pole Pieces: 75mm tappered to 25mm
Mag. Field: 17KG ±5% at 10mm airgap
Energising Coils: Two of approx. 13W each
f) Constant Current Power Supply, Model DPS-175

g) Gaussmeter, DGM-202

The experiment is complete in all respect.

We offer D.C. Motor Study useful for control labs. A d.c. motor is commonly used as an actuator in many industrial control applications because of its features - large torque and ease of speed variation. The dynamic characteristics of such a system therefore depends on the motor parameters viz., moment of inertia, coefficient of friction, time constant and also the resistance and inductance of the control winding. It is therefore important to experimentally determine the mechanical and electrical parameters of the d.c. motor and also to evaluate its transfer function.
The present unit is designed to study a small permanent magnet d.c. motor. A still smaller generator directly coupled to the motor is used for the dual purposes of speed signal pick up and providing electrical loading. The shaft speed in rpm is displayed automatically on a 4-digit panel meter.
Highlights of Equipment:

• Torque-speed characteristics
• Determination of motor parameters - inertia and friction
• Digital display of time constant
• Transfer function evaluation

Experiments:

• Determination of torque-speed characteristics
• Evaluation of inertia and friction parameters
• Determination of back e.m.f. constant
• Determination of time constant
• Determination of transfer functions of the Motor and the Generator

Features and Specifications

• Study of a 12V, 8W d.c. motor
• Small generator (2W) for speed pick up and loading
• 4-digit speed display
• 3-digit time constant display
• 3½ digit voltmeter and current meter for d.c. measurement
• IC regulated power supply
• Supporting literature with experiment details

We offer A.C. Position Control System, ACP-01 useful for control labs. 2-phase ac servomotors have been traditionally used for position/ speed control applications especially in light weight, precision instrumentation area in airborne systems.
The present unit is designed around a 12V ac servomotor and exposes the basic characteristics and dynamics of a position control system. A block diagram of the system is shown in figure below.
Besides introducing the basic features like balanced modulation of the error signal, phase reversal around the set point and phase difference between the reference and control phases of the motor, the experiment involves study of the step response of the closed loop system.Being a mechanical system the response is too slow for a comfortable viewing on a CRO, except on an expensive storage oscilloscope. A microprocessor based waveform capture/display card in the unit stores the step response in real time and displays the same oncesteady state is reached.

Highlights of Equipment:

• 2-phase A.C. Servomotor
• Servo Potentiometer for position sensing
• Transient response capture/display
• In-built rms voltmeter on panel

Experiments:

• Error detector characteristics, phase reversal
• Amplifier gain measurement
• Phase difference between control and reference windings
• Step response study

Features and Specifications

• 2-phase servomotor – 12 volt/phase, 50Hz, 10 watt
• Power amplifier for driving
• Servo potentiometer type error detector
• In-built 10.00 volt (rms) panel meter
• Step response capture/display card
• Detailed literature with typical results included
• Complete unit except a measuring CRO

The experiment is complete in all respect.

We offer e/m Experiment, EMX-01, our arrangement for measuring e/m, the charge to mass ratio of the electron is a very simple set-up. It is based on Thomson’s method. The e/m-tube is bulb-like and contains a filament, a cathode, a grid, a pair of deflection plates and an anode. The tube is filled with helium at a very low pressure.Some of the electrons emitted by the cathode collide with helium atoms which get excited and radiate visible light. The electron beam thus leaves a visible track in the tube and all manipulations on it can be seen. The tube is placed between a pair of fixed Helmholtz coils which produce a uniform and known magnetic field. The socket of the tube can be rotated so that the electron beam is at right angles to the magnetic field. The beam is deflected in a circular path of radius r depending on the accelerating potential V, the magnetic field B and the charge to mass ratio e/m. This circular path is visible and the diameter d can be measured and e/m obtained from the relation
e/m = 8V/B²d ²
This set-up can also be used to study the electron beam deflection for different directions of the magnetic field by varying the orientation of the e/m-tube.
Description of the Experimental Set-Up
The central part of the set-up is the e/m-tube. This is energized by
(i) Filament current supply
(ii) Deflection plates voltage supply
(iii) Continuously variable accelerating voltage supply to the anode.
Specifications
Helmholtz coils of radii: 14 cm
Number of turns: 160 on each coil
Accelerating Voltage: 0 – 250V
Deflection plates voltage: 50V – 250V
Operating Voltage: 220V AC/ 50Hz

We offer D.C. Position Control System, DCP-01 useful for control labs. This unit provides the students an opportunity to study and operate a practical electromechanical angular-position-control system. The system is built around a good quality permanent magnet armature-controlled d.c. motor, speed reduction gear-set, potentiometric error detector using special 360° revolution servo potentiometers, a tacho generator for velocity feedback and associated electronic circuits. The motor unit is housed in a separate cabinet with transparent panels for easy viewing.

>> Highlights of Equipment:

• Compact system - no mechanical hassles
• Simplified operation
• μP based storage of response
• Positive/Negative tachogenerator feedback

Experiments:

• Operation of the position control system for different values of the forward gain to angular position commands
• Step response studies for various values of forward gain
• Study of the effect of velocity feedback on the transient and steady state performance of the system as well as its stability

Features and Specifications:

• Position control of a 12V, 1A d.c. gear motor (50 rpm)
• Provision for positive and negative tacho generator feedback
• Tacho constant: 2V/1000 rpm approximately
• Calibrated dials for reference and output position: resolution 1°
• Servo-potentiometers with full 360° rotation
• μP based waveform capture/display card
• Built-in 3½ digit DVM for signal measurements
• Built-in step signal and IC regulated power supplies for electronic circuits
• Separate unit for motor in a see-through cabinet
• 110V±10%, 60Hz mains operation
• Literature and patch cords included
• Essential accessories - a CRO

We offer Digital Gauss meter, DGM-202, it operates on the principle of Hall Effect in Semiconductors. A semiconductor carrying current develops an electromotive force, when placed in a magnetic field, in a direction perpendicular to the direction of both electric current and magnetic field. The magnitude of this e.m.f. is proportional to the field intensity if the current is kept constant. This e.m.f. is called the Hall Voltage. The small Hall Voltage is amplified through a high stability amplifier so that a millivoltmeter connected at the output of the amplifier can be calibrated directly in magnetic field unit (Gauss).

Features

• Wide Range (1G to 20KG)
• Excellent Linearity
• Excellent Stability
• Interchangable Hall Probes

Applications

• Wide application in industry where accurate measurements of magnetic field is required.
• Measurement of steady magnetic
• field e.g. in loud speakers, dynamo, moving coil instruments etc.
• Useful in laboratory experiment involving measurement of magnetic field.
• With easy interchangeability of Hall Probe, same Gauss-meter can be used with both transverse and axial probe.

Specifications
Resolution: 1 Gauss at 1 kilo Gauss range
Range: 1KG and 10KG with 100% over ranging
Accuracy: ±0.5%
Temperature: Upto 50°C
Display: 3½ digit, 7 segment LED DPM with auto polarity and overflow indication
Power: 220V ±10%, 50Hz
Transducer: Hall Probe – InAs
Special Feature: Indicate the direction of the magnetic field
Weight: 3Kg
Dimensions: 280mm X 255mm X 120mm

High Voltage Power Supply, EHT-11:
We offer precision High Voltage Power Supply very useful for general laboratory and R&D labs. EHT-11 is designed to meet the power requirements of a broad range of radiation detectors: G.M. Counters, ionization Chambers, Scintillation Detectors, Photo-multiplier Tubes and any application where a high voltage source with high degree of regulation and stability is required.
Specifications

Output: 0-1500V continuously adjustable
Current: 1mA (max.)
Polarity: +ve or -ve, as required
Regulation: ±0.05% for 0 to 1mA load
Stabilization: ±0.02% for ±10% mains variation
Display: 3½ digit, 7 segment LED DPM
Connection: Output through a amphenol connector on the front panel
Protection: Fully protected against overload and short circuit by current limiting technique
Power requirements: 220V ±10%, 50Hz
Weight: 5Kg
Dimensions: 240mm X 390mm X 130mm.

We offer Study of a Modulation and Demodulation with Built-in Carrier Frequency Source (Solid State), the following studies can be carried out with this set-up:

1. Carrier signal testing.
2. Variation of modulated wave with the modulation signal.
3. Study of detector circuit.

The experimental set-up is provided with a built-in power supply.
Accessories Required:
(i) Function Generator, FG-01
(ii) Oscilloscope
The set-up is so designed that no high voltage is exposed and hence safe in handling by the students.

We offer a classroom experimental setup of ESR (Electron Spin Resonance). In this method, use is made of the Zeeman interaction of the magnetic dipoles associated with the nucleus or the electron, when placed in an external magnetic field. Accordingly, they are identified as NMR (Nuclear Magnetic Resonance) or ESR (Electron Spin Resonance). This form of spectroscopy finds many applications in many diverse branches of Physics, Chemistry and Biology.
This set-up is designed, keeping in mind the basic objectives of a classroom experiment. The observation of ESR in low magnetic field and in a radio frequency makes this apparatus very simple, inexpensive and within reach of every Post Graduate laboratory.
The Electron Spin Resonance experiment comes complete along with following accessories:
(i) Helmholtz coils with an attachment for the ESR-HC
(ii) ESR Sample: DPPH
(iii) R.F. Oscillator (10MHz to 19MHz)

Offering digital microscope( DMS-01) which is a powerful device & which can be used is almost any application where magnification is required. It can be used as a traveling microscope, biological microscope, student microscope, industrial microscope etc.

• Laboratory Examination
• Industrial Inspection
• Scientific Research
• Medical analysis

Features

• Adjustable Focus (10-60X, 230X)
• High-precisions lens
• LED illumination switchable and adjustable
• Instant snapshots and time-lapse video recording
• Support Multi languages

Specifications

• Effective Pixel 320x240, 640x480 1280x1024, 1600x1200
• Resolution 1.3 Megapixel
• Image 1.4" CMOS sensor
• Signal Interface USB 2.0
• White Balance Automatic
• USB line 1.5 Meters

System Requirement

• Pentium III and 256MB Ram above
• Windows XP/Vista/Windows 7
• Available USB 2.0 port
• 17" PC display (Preferable)
• CD ROM Drive

Package Content

• USB digital microscope - 1
• Metal tripod stand - 1
• Brick Stand - 6
• Calibration pattern - 1
• CD driver with measurement S/W - 1
• Travel bag - 1

Measurement Function

• Measure images by length, angle, area etc.
• Compare images using cross wire, ruler, circles
• Option for time stamping
• Save, email, print image.

We are offering Ionisation Potential Setup IP-01 useful in Physics and Material Science Lab. The ionisation potential i.e. the energy required to remove an electron completely from the atom.
The experiment is consists of the following:

• Argon filled tetrode
• Filament Power Supply
• Power Supply for VG1K
• Power Supply for VKA
• Power Supply for VG2K
• Saw tooth waveform for CRO display
• Multirange Voltmeter
• Multirange Ammeter

All this is housed in a cabinet with meters and adjustment knobs on the front panel. The set-up can also directly display the anode current variation with VG2K on the oscilloscope screen. It can thus be used as a laboratory experiment as well as for demonstration to a group of students.
Analysis of the Data:
Point by point data for the anode current with VG2K changing in steps of 1V at VG1K equal to 1.5V and VKA equal to 3.0V can be verified experimentally by drawing a graph. The on-set of the anode current and the point where the slope of the current changes can be determined by locating the points of intersection of the lines. These points are at 16V and 31V respectively. The former corresponds to the ionization potential and the latter for the ionization again. The average value of the ionization potential thus found is 15.5 eV compared with the accepted value of 15.6eV.

We offer Compensation Design useful for control labs. Practical feedback control systems are often required to satisfy design specifications in the transient as well as steady state regions. Cascade compensation is most commonly used for this purpose. This unit has been designed to enable the students to go through the complete design procedure and finally verify the performance improvements provided by compensation. The experimental set-up is accompanied by the supporting literature which becomes of vital importance as a major part of the experiment involves theoretical design of compensation networks.
Highlights

• Design and test cascade compensator
• Simulated system for accurate results
• Built-in compensator – only passive external components
• Built-in signal sources

Experiments

• Lag/Lead compensation in the frequency domain
• Lag/Lead compensation in the s-plane
• All the above design problems may be undertaken for a very wide range of design specifications
• The implementation of the compensation network has been made very convenient by a pre wired amplifier with calibrated gain

Features and Specifications

• Simulated ‘uncompensated’ system having adjustable damping. Peak percent overshoot MP, variable from 20% to 50%, and steady state error variables from 50% to 0.5%
• Compensation network implementation through built-in variable gain amplifier. Gain is adjustable from 1 to 11
• Built-in square and sine wave generators for transient and frequency response studies. Frequency adjustable from 25Hz – 800Hz (approx.)
• Essential accessory: a CRO

The experiment is complete in all respect, except a CRO.

We offer Stroboscope usefull for control labs. Measurement of the speed of a rotating shaft is a common requirement in many industrial and laboratory applications. Stroboscope, is a convenient-to-use, direct reading speed measuring instrument. A highly stable function generator IC based circuit provides the basic variable frequency timing pulses. These are read on an IC based LCD/LED counters with direct speed display in rpm. The flasher unit generates the high intensity flashes at a suitably scaled rate directed towards the rotating shaft. Precision potentiometer's makes the task of speed setting very precise. The portable model, fitted into a light weight and strong plastic body is more suited for industrial / class room environment. Operating instructions are included in the Instruction manual accompanying the unit.
Highlights

• Non-contact speed measurement
• High intensity flashes
• Direct speed reading in RPM
• No shaft modification

Features and Specifications

• Speed range: 500-9900 rpm
• Crystal Controlled accuracy
• Mains Operation
• Display: 4 digit LED
• Freq. control: 10 turn Potentiometer
• Study Desktop Model
• Suitable for class room environment

The experiment is complete in all respect.

We offer Study of Temperature Transducers, STT-01usefull for control labs. Measurement of temperature is an important task in a large number of physical processes. A transducer in a device which converts the temperature information into an electrical signal usually voltage, for an automated processing. A very wide variety of temperature transducers are commonly available which differ from each other with regards to there:
(a) Range of operation
(b) Sensitivity and linearity
(c) Accuracy, Stability and Repeatability
(d) Speed of response
The present experiments has been designed to study the input-output characteristics of some common transducers like, thermistors (PTC and NTC), thermocouple, semiconductor sensors and may be extended to also study the temperature coefficients of resistance.

>> Highlights:-

• Temperature controlled oven with digital display
• Instrumentation amplifier with gain switching
• Digital voltmeter
• Interfacing circuits for common transducers

>> Experiments:-

• Temperature-output voltage characteristics of the following transducers in the temperature range of room temperature to 150°C and determination of their parameters

• Thermocouple

- Chromel - Alumel
- Copper - Constantan

• Thermistors
• Semiconductor sensor (type AD590) upto 90°C only

>> Features and Specifications:-

• Temperature controlled oven upto 150°C with digital temperature display
• Digital voltmeter on the panel for sensor output measurement
• Built-in interfacing circuit and switched gain instrumentation amplifier
• IC regulated power supplies and detailed manual

The experiment is complete in all respect.

We offer Digital Gaussmeter, DGM-103, it operates on the principle of Hall Effect in Semiconductors. A semiconductor carrying current develops an electromotive force, when placed in a magnetic field, in a direction perpendicular to the direction of both electric current and magnetic field. The magnitude of this e.m.f. is proportional to the field intensity if the current is kept constant. This e.m.f. is called the Hall Voltage. The small Hall Voltage is amplified through a high stability amplifier so that a milli-voltmeter connected at the output of the amplifier can be calibrated directly in magnetic field unit (gauss).
Features

• Differential mode facility
• Wide Range (1G to 40KG)
• Excellent Linearity
• Excellent Stability
• Easy replacement of Hall Probe

Applications

• Wide application in industry where accurate measurements of magnetic field is required.
• Measurement of steady magnetic field e.g. in loud speakers, dynamo, moving coil instruments etc.
• Useful in laboratory experiment involving measurement of magnetic field.
• With the differential mode facility, the instrument is especially useful for testing the homogeneity/variation of magnetic field in a particular region.

Specifications
Range: 0-2KG, 0-20KG & 0-40KG
Resolution: 1G at 0-2KG range in normal mode
: 1G at 20KG & 40KG range in differential mode
Accuracy: ± 0.5%
Temperature: Up to 50°C
Display: 3½ digit, 7 segment LED DPM with auto polarity and overflow indication.
Power: 220V ±10%, 50Hz.
Transducer: Hall Probe – InAs.
Special Feature: Indicate the direction of the magnetic field
Weight: 3Kg.
Dimensions: 280mm X 255mm X 120mm.

We offer Study of Stepper Motor useful for control labs. This experimental set-up aims at providing an exposure to the basic operation of a stepper motor, its drive and logic, and limitations as far as the internal dynamics is concerned.
Highlights

• Stepper motor operation through pulse circuit
• Stepper motor operation through 8085 mp kit
• Built-in programs in EPROM
• Dynamic response study

Experiments

• Manual stepping through push button switch. Measurement of step angle.
• Speed and direction control logic by recording the pulse sequence.
• Study of resonance effect at various speeds
• Display and measurement of the dynamic characteristics of the motor in the wobble mode.
• Calculation of ¿¿¿single stepping¿¿¿ and ¿¿¿slew¿¿¿ regions.
• Programming the microprocessor kit to implement features like direction, speed, angle of rotation, number of steps or an arbitrary motion
• Study of the effect of inertial and frictional loading on the dynamic performance

Features and Specifications

• Single stepping and free running modes of operation with speed variation and direction reversal - internal TTL circuit.
• 360¿¿ motion Servo-Potentiometer position -pickup for motor dynamics
• Operation through microprocessor kit ¿¿¿ sample control programs provided
• Stepper motor specification

¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿ Torque: 2.8 Kg-cm
¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿ Step angle: 1.8¿¿
¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿ Power: 12V, 1A/phase

• Essential accessory ¿¿¿ a CRO

The experiment is complete in all respect except a CRO.

We offer Study of A Transistor Amplifier (Rc Coupled) Cum Feed-Back Amplifier, RC-01 with this following studies can be carried out with this set-up

1. Study of the basic circuit of a RC Coupled Amplifier.
2. Frequency response of RC Coupled Amplifier.
3. Effect of negative feedback on the gain and frequency response of the amplifier
4. Effect of positive feedback on the gain and frequency response of the amplifier.
5. Verification of the condition of oscillation.
6. Study of different classed of amplifier.

>> Accessories Required:-
(i) R.F. Oscillator
(ii) True RMS A.C. Millivoltmeter, ACM-102
The set-up is so designed that no high voltage is exposed and hence safe in handling by the students.

We offer A.C. Servomotor Study useful of control labs. Two phase a.c. servomotor is one of the very important electromechanical actuators having applications in the area of control systems. The study of its operating principle and features form a part of the first course on automatic control systems in electrical engineering curriculum.
Important subsystems of the unit includes:
(a) an integrated speed sensor with 4-digit display in r.p.m.
(b) an electrical loading system to compute torque
(c) a time-constant measurement circuit with 3-digit display in milli seconds
(d) a three step a.c. source with built-in r.m.s. voltmeter, and
(e) a digital voltmeter on the panel for load measurement
The unit has been designed such that expensive equipment like storage CRO is not needed. Also the hassle of direct torque measurement using spring balance etc. is avoided by linearization of the motor characteristics analytically.
Highlights of Equipment

• Torque computation through electrical loading
• Determination of motor para-meters - inertia and friction
• Digital display of time constant
• Transfer function evaluation

Experiments

• Inertia and friction parameters
• Time constant
• Transfer function

Features and Specifications

• 2-phase a.c. servomotor - 12V/ 50Hz per phase.
• Small generator for loading.
• 4-digit speed display.
• 3-digit time constant display.
• 3½ digit r.m.s. voltmeter .
• 3½ digit d.c. panel meter.
• Voltage regulated internal supplies.
• Detailed literature with sample results.

The experiment is complete in all respect.

Study of a Solid State Power Supply, SSPS-02:
We offer Study of a power supply (Solid State) physics ans electronics experimental setup. The Set-up consists of a step-down transformer, a rectifier circuit (can be used as a half-wave or a full-wave rectifier), a filter circuit (an inductance and two capacitors) - the arrangement can be used for the study of various configuration of filters and a regulator circuit. A built-in electronic load is used to smoothly vary the load current while a digital panel meter on the board measures the load current and load voltage.
FEATURES:
1. Study of rectification:
(a) Full wave rectification
(b) Half wave rectification
(c) Bridge rectification.
2. Study of AC component(Ripples):
(a) Efficiency of various type of filters L, pie, T type etc.
(b) The effect of load
(c) The effect of regulation.
3. Regulation characteristics:
(a) The effect of load on regulation
(b) The effect of change in mains voltage.
4. Electronic Load: To draw the load current smoothly.
Specifications:
Output: 0-12 volts
Max. current: 200 mA
Regulation: 1%
Metering: Output voltage/ current on the switchable DPM
The experimental set-up is complete in all respect, except a multimeter and a CRO.

We offer Study of Magnetic Levitation System useful for control labs. Magnetic Levitation, lifting of objects under the influence of a magnetic field, has numerous application including some advance locomotives designed on the repulsive force of a magnet. The present unit, based on the attractive force of an electromagnet, is inherently unstable. There is no way to keep an iron object suspended in air by manually adjusting the current in the electromagnet. Even a feedback control with forward path gain control alone is ineffective. These facts are brought out by studying and experimenting with the dynamics of the system. The next task consists of the design of suitable controller and implementing the same to achieve the desired objective. A sound knowledge of MATLAB and its availability should be highly desirable, though not essential, for the conduct of this experiment. The basic theory, analysis and sample calculation are described in the accompanying literature.
Highlights

• Object suspended in air by magnetic force ¿¿¿ excellent visual impact
• Controller design to maintain stability¿¿
• Up-down position setting by reference control

Experiments

• To develop the transfer function of the system through laboratory
• To design/implement PD and lead compensation with different parameter
• To simulate the system in MATLAB and study in detail various control option and their response

Features and Specifications

• Object suspended in air by magnetic force
• Controller design to maintain stability
• Position changing by reference
• Built-in power supplies, meters etc
• 220V/50Hz operation¿¿
• Detailed technical literature included

¿¿The experiment is complete in all respect.

We offer Magnetic Field Measurement Apparatus, the experiment consists of two coils, Constant Current Power Supply and Gaussmeter. The Gaussmeter probe is mounted on a rail with a scale. It can move smoothly and precisely for measurement of magnetic field along the centre of the coils.
The following studies can be carried out with the set-up:
1. Study of magnetic field due to one coil and calculation of its diameter.
2. Study of principal of super-imposition of magnetic field due to 2 coils by keeping the distance between the coils at a, greater than a and less than a, where a is the radius of the coil.
Legend:
Line 1- Magnetic Profile when the distance between the coils is > a
Line 2- Magnetic Profile when the distance between coils is = a
Line 3- Magnetic Profile when the distance between coils is < a- Superimposition overlaps completely
Apparatus consists of the following:
1. Digital Gaussmeter
Range: 0-200
Resolution: 0.1G
Accuracy: ± 0.5%
Display: 3½ digit 7 segment LED with autopolarity.
2. Two Coil
Diameter: 200mm
Number of turn: 1000
3. Constant Current Power Supply
Current: 0-0.5A Smoothly adjustable
Line Regulation: ± 0.2%for 10% mains variation.
Load Regulation: ± 0.2 % for 0 to full load.
Display: 3½ digit 7 Segment LED Display.
Protection: Against overload/ short circuit.
The 2 coils are mounted on platform one coil is fixed and other coil move smoothly on a rail along with the axis of the coils.
The experiment is complete in all respect.

We offer PID Controlled Oven, this is high quality temperature controlled oven suitable for Four Probe Set-up, testing of electronic components & study of temperature transducers etc.. The oven has been designed for fast heating and cooling rates which enhances the effectiveness of the controller. While the basic design of the controller is around the PID configuration for its obvious advantages, wastage of power is avoided by using a Pulse Width Modulated (PWM) switch. This combination has the advantages of both on-off controller and linear PID controller. The result is a good stable and accurate temperature control. A platinum RTD has been used for sensing the temperature. A Wheatstone bridge and an instrumentation amplifier are used for signal conditioning. Feedback circuit ensures offset and linearity trimming to a great degree of accuracy. The set and measured temperature are displayed on 3? digit DPM through selector switch.

Specifications of the Oven :
Temperature Range: Ambient to 200°C .
Resolution: 0.1°C.
Short Range Stability: ±0.2°C.
Long Range Stability: ±0.5°C.
Measurement Accuracy: ±0.5°C (typical).
Oven: Heating Chamber Inner Diameter: 25mm, Height: 100mm (Specially designed for Four Probe Set-Up/ Component testing)
Sensor: RTD (A class).
Display: 3½ digit, 7 segment LED (12.5 mm) with auto polarity and decimal indication.

We offer Study of Synchro Devices useful for control labs.
Highlights

• Synchro transmitter-receiver pair with calibrated dials
• Locking system for receiver rotor
• Receiver use as control transformer
• Built-in balanced demodulator circuit
• Panel meter for ac/dc voltages
• All internal power from the 220 V/50 Hz mains¿¿
• Only an external CRO required

Experiments

• Basic characteristics study - stator voltages as a function of the rotor angle using the built-in ac voltmeter. This shows the space variation of the three voltages, V_S1S2, V_S2S3, and V_S3S1, causing rotation of the resultant magnetization in the stator which is fundamental to the error detection process.
• Operation and error study of the transmitter-receiver pair as a simple open loop position control at a very low torque. This is a rarely used application but is used to demonstrate the direction of the resultant magnetic field in the receiver.
• Plotting the error voltage output as a function of the transmitter rotor angle with the receiver rotor locked. Observing the 180¿¿ phase reversal around the zero error is significant as this the basic method through which the direction of the error is detected in an ac system
• Use of balanced demodulator to develop dc error signal with appropriate polarity and compare it with the ac error. This block would be needed if a mixed system were to be designed using both dc and ac components.

The experiment is complete in all respect except a CRO.

Microprocessor Device Controller, MDC-01:
We offer Microprocessor Device Controller use full for control labs. This unit has been designed to train the students to handle basic input - output operations of the 8085 microprocessor through 8255 ports. The power supply, drivers and other hardware are pre-wired resulting in a greater reliability of operation. The students are expected to enter a few suggested programs and also to develop their own programs for a variety of input-output operations.

Highlights

• Sequence control of 8 LEDs through 8255 port
• Control of 2 relays
• Operating a 7-segment display
• Switch state input through 8255 port
• SID/SOD Operation

Experiments

• Light the 8 LEDs in a cycle, in binary sequence, as a bar graph display etc.
• Operate the 2 relays with software controlled timing
• Operate the 7-segment display through segment control
• Sense the state of the 4-switches as input and send out suitable signals to various output devices
• Study of SID/SOD commands

Features and Specifications

• System comprises of a main unit and a mp kit
• The main unit houses all the I/O devices, viz. LED’s, relays, 7-segment display, switches and their drivers/interfacing circuits
• The status of the relays and switches are displayed with the help of lamps mounted on the panel
• Supporting literature with experiment details

The experiment is complete in all respect.

We are offering d.c. speed control system:
Introduction
Closed loop speed control of dc motor is a common experiment for studying various features of automatic control systems like control, regulation and disturbance rejection.
The present unit is designed to demonstrate the working of PWM and SCR based controllers and show the resulting waveforms of the voltage supplied to the motor. Measurement of the timings on the waveforms under various conditions has been suggested to get a good insight into the operation of the system. The experiment is complete with all the sub-systems and a detailed operating literature is included which introduces the basic theory, suggested experiments and an interpretation of the results.
An external CRO is all that is needed to view the waveforms and measure the timings.
Experiments

• Open loop speed control for PWM controller, with and without load
• Open loop speed control for SCR controller, with and without load
• Closed loop speed control for PWM controller with load
• Closed loop speed control for SCR controller with load
• Observation and measurements on the voltage waveforms

Features & specifications

• Speed control of a 12V, 4W permanent magnet dc motor
• Speed Range: 0 to 2000 rpm (typical)
• Opto-interrupter based speed sesing
• 4-digit speed display in rpm
• Electronic tachogenerator for feedback
• Separate unit for motor in a see-through cabinet
• Smooth, non-contact eddy current brake for loading
• Built-in 3½ digit DVM for signal measurements
• 220V±10%, 50Hz mains operation
• Supporting literature and patch cords included
• Essential accessory – a CRO

We offer a classroom experimental setup of ESR (Electron Spin Resonance Spectrometer, ESR-105). In this method, use is made of the Zeeman interaction of the magnetic dipoles associated with the nucleus or the electron, when placed in an external magnetic field. Accordingly, they are identified as NMR (Nuclear Magnetic Resonance) or ESR (Electron Spin Resonance). This form of spectroscopy finds many applications in many diverse branches of Physics, Chemistry and Biology.

>> Features

• FET based marginal R.F. Oscillator
• Digital display of frequency
• Excellent peaks display
• Digital display of Helmoltz Coil Current
• Compatible with general purpose CRO in X-Y mode

This set-up is designed, keeping in mind the basic objectives of a classroom experiment. The observation of ESR in low magnetic field and in a radio frequency makes this apparatus very simple, inexpensive and within reach of every Post Graduate laboratory.
** The Electron Spin Resonance experiment comes complete along with following accessories:
(i) Helmholtz coils with an attachment for the ESR-HC
(ii) ESR Sample: DPPH

Offering Study of Planck's Constant, PCA-01.
We offer Study of Planck's Constant very useful for Physics and Material Science labs. Several proposals to measure the Planck’s Constant for didactic purposes, using the current – voltage (I-V) characteristics of a light emitting diode (LED) have been made quite regularly in the last few years. The physical interpretation however is not completely clear and this has raised many discussions, which have been published almost with same regularity as the proposals themselves.
The present experiment is based on diode current for V<V₀, using the diode law.
l = l₀ exp [-e(V₀ – V)/ η_kT]
The correct method to determine the real height of the potential energy barrier V0 is to directly measure the dependence of the current on temperature keeping the applied voltage V slightly below V₀.
Compare with previous methods, this determination of V0 is more precise and more accurate and at the same time the physical interpretation is more transparent. The Planck’s constant is then obtained by the relation
h = e V₀ λ/c
The set-up is a self contained unit. All the necessary facilities and measuring devices are built in a single unit, as a result only minimum of external connections need to be made.
The experiment is complete in all respect.

We offer Study of Second Order Networks useful for control labs. Second order networks are important because of the fact that these are the simplest networks that produce the complete range of transient response ¿¿¿ from over damping to near oscillations. Although theoretical discussions are normally confined to passive RLC networks, such networks are limited in their performance due to the rather large resistance of any reasonable value inductance that might be constructed to operate at frequencies of few kHz. In the present unit active RC-network has been designed which span the complete behavior of an equivalent passive RLC network. The user thus has the experience of studying a near ideal passive second order network complete with all theoretical computations and their experimental verifications.
Highlights

• Active second order network
• Damping control¿¿¿over-, critical-, and under-damping
• Built-in sine wave signal
• Needs an external CRO for response study
• Operates with 220V/50 Hz
• Detailed technical literature and experiment results supplied

Experiments

• Observe and trace from the CRO screen the step response for different values of ¿¿.
• Compute approximate values of equivalent network parameters.
• Plot the frequency response for various of ¿¿ and observe resonance

Features and Specifications

• Active RLC network using 3-Op Amps
• Damping 1.1-0.1 (approx)
• Square Wave 35-700 Hz., 0-1V (typical)
• Sine Wave 35-700 Hz., 0-1V (typical)
• Essential accessory: a CRO

The experiment is complete in all respect, except a CRO.

We offer a specially designed experimental setup for
1) Determination of Planck's Constant and Work Function of Materials by Photoelectric Effect
2) To verify Inverse square law of radiation using a photoelectric cell
The Apparatus consists of the following:
1. Photo Sensitive Device: Vacuum photo tube.
2. Light source: Halogen tungsten lamp 12V/35W.
3. Colour Filters: 635nm, 570nm, 540nm, 500nm & 460nm.
4. Accelerating Voltage: Regulated Voltage Power Supply
Output: ±15V continuously variable through multi-turn pot
Display: 3½ digit 7-segment LED
Accuracy: ±0.2%
5. Current Detecting Unit, Digital Nano ammeter: It is high stability low current measuring instrument
Range: 1000 mA, 100 mA, 10 mA & 1mA with 100 % over ranging facility
Resolution: 1nA at 1mA range
Display: 3½ digit 7-segment LED
Accuracy: ±0.2%
6. Power Requirement: 220V ± 10%, 50Hz. or 110V ± 10%, 60Hz. as required.
7. Optical Bench: The light source can be moved along it to adjust distance between the light source and the photo-tube, scale length is 400mm. A tube is provided to install colour filter and a focus lens is fixed in the back end.
The set-up is complete in all respect, no additional accessory required.

We manufacturer wide variety of Laboratory Experiment/ Measuring equipment for Post Graduate and Under Graduate Physics Laboratories. Details of all products manufactured by us are available on our website sestechno.com.

We offer precision Digital Picoammeter very usefull in general laboratory and R&D labs. This is a very versatile multipurpose equipment for the measurement of low dc currents. It has 6 decade ranges with 100% over-ranging from 10^-9A to 10^-4A. For the ease, readings are directly displayed on a 3¿¿ digit DPM.
The instrument uses a well designed precision FET input electrometer operational amplifier AD549, which offers the lowest input bias currents (50fA with ¿¿5V supplies) available in any standard operational amplifier. The excellent characteristics of AD549, ultra low bias current, low offset voltage, low drift and low noise have been fully utilized to obtain best results in the present picoammeter. The first operational amplifier AD549 is used in low level current to voltage configuration and the output has been directly read on a 3¿¿ digit panel meter. The instrument is capable of accepting either polarity of the input current. Well regulated power supplies are designed for using the instrument up to 10% changes in a.c. main¿¿¿s voltage.
Features

• Measures current down to 1pA
• All solid state and IC design
• Very low offset current.

Specifications
Multiplier: X1, X10, X10², X10³ , X10⁴ , X10⁵
Accuracy: 0.2% for all ranges
Resolution: 1pA, 10pA, 100pA, 1nA, 10nA, 100nA
Input Resistance: 2.5K¿¿, 0.25K¿¿, 25¿¿, 2.5¿¿, 0.25¿¿, 0.025¿¿
Display: 3¿¿ digit, 7 segment LED (12.5mm height) with¿¿ auto polarity and decimal indication.
Input: Through Amphenol connector.
Power Supply: 220V¿¿10%, 50Hz.
Weight: 2.5Kg.
Dimensions: 240mm X 275mm X 120mm.

We offer Digital Gauss meter, DGM-102, it operates on the principle of Hall Effect in Semi-conductors. A semiconductor carrying current develops an electromotive force, when placed in a magnetic field, in a direction perpendicular to the direction of both electric current and magnetic field. The magnitude of this e.m.f. is proportional to the field intensity, if the current is kept constant. This e.m.f. is called the Hall Voltage. The small Hall Voltage is amplified through a high stability amplifier so that a millivoltmeter connected at the output of the amplifier can be calibrated directly in magnetic field unit (gauss).

Features

• Mag. Field Measurement
• Excellent Linearity
• IC Controlled Circuit
• Excellent Stability

Applications

• Wide application in industry where accurate measurements of magnetic field is required.
• Measurement of steady magnetic field e.g. in loud speakers, dynamos, moving coil instruments etc.
• Useful in laboratory experiments involving electromagnets.

Specifications
Range: 0-2KG & 0-20KG
Resolution: 1G at 0-2KG range
Accuracy: ±0.5%
Temperature: Upto 50oC
Display: 3½ digit, 7 segment LED DPM with auto polarity and over flow indication
Power: 220V ±10%, 50Hz
Transducer: Hall Probe – InAs
Special Feature: Indicate the direction of the magnetic field
Weight: 3Kg
Dimensions: 280mm X 255mm X 120mm

We offer Characteristics of Semiconductors Diodes, this experiment set-up consists of the following:

1. Diodes: 1N4007, 1N34, 5.1V Zener and LED.
2. 3½ digit DPM for voltage measurement
3. Precision resistances for measurement of forward and reverse current.
4. IC regulated power supply.

The following studies can be carried out with this set-up:

1. Forward and reverse characteristics of both Ge, Si diodes & LED’s.
2. Study of Zener diode characteristics.

The set-up is so designed that no high voltage is exposed and hence safe in handling by the students.

We offer PID Controller, PID-01 useful for control labs. The experimental unit consists of simulated building blocks like error detector, dead time, integrator and time constants, which may be configured into a variety of systems. A PID section with adjustable proportional gain, derivative and integral time constants provide the control action. Built-in set value, square and triangular sources enable the students to study the response on a CRO. The literature includes system description, theory, experimental procedure and typical results. An important feature of the system is that the simulated blocks are designed to operate at frequencies suitable for CRO viewing.

Highlights

• PID-action study on CRO
• Simulated blocks for flexible system
• Time delay (transportation lag) block
• Synchronised square and triangular source for flicker free display

Experiments

• Open loop response of various process configurations (10 in all)
• Study of closed loop response for above
• P, PI, PD and PID design and performance evaluation in each case

Features and Specifications
Simulated blocks – dead time (transportation lag), integrator, time constants, error detector and gain
PID Controller (configurable as P, PI, PD or PID)
Prop. Band: 5% to 50% (Gain 2-20)
Integral time: 10msec - 100msec
Derivative time: 2-20msec
Built-in signal sources
Set value: -1V to +1V
Square wave: 1V p-p (min.) at 40Hz (typical)
Triangular wave: 1V p-p (min.) at 40Hz (typical)
Built-in 3½ digit DVM for d.c. measurements
Built-in IC regulated power supply
Detailed literature and patch chords included
Essential accessory – a CRO

The experiment is complete in all respect, except a CRO.

We offer high quality Traveling Microscope whose bed is of a heavy casting, thoroughly aged and machined, is fitted with leveling screws. On the dovetailed guide ways slide the carriage which can be clamped at any position by means of a thumbscrew. A sliding carriage slides along a gunmetal Vertical pillar fitted on the horizontal carriage. The slow motion guide bars are made of sturdy material and the motion is very smooth.
Microscope Tube
Indeclinable in any angle. True vertical and horizontal positions marked focusing.
Guide Ways
The guide ways over which slides the carriage is made of gunmetal and this makes the instrument Rust Proof, because this is the part which is directly exposed to the weather.

Scales and Verniers
Made of lifetime Stainless Steel.
Optics
(i) True achromatic objective with 7.5 cm. focusing distance from object
(ii) 10X Ramsden Eyepiece with fine cross wire
Scale and Vernier
(i) Horizontal scale : 18cm divided at 1mm interval.
(ii) Vertical scale : 16cm divided at 1mm interval.
(iii) Screw gauge dial : 100 divisions with a least count of 0.01mm.

We offer Study of Astable & Monostable Multivibrator using Timer Ic, TYPE-555, the following studies can be carried out with this setup:

1. Operation as a free running multivibrator
2. Operation as a monostable multivibrator
3. Operations as a preset time delay.

The set-up is so designed that no high voltage is exposed and hence safe in handling by the students.

We offer Study of 741 Applications, 741-02.
>> Features:
• Study of linear and non linear applications as:
- Integrator
- Differentiator
- Summer
- Subtractor
- Voltage to Current converter
- Current to Voltage converter
- Astable Mode
- Precision rectifier
• Built-in power supply
• Built-in square wave and triangular wave Generator
• Built-in current source.
The set-up is so designed that no high voltage is exposed and hence safe in handling by the students.

We offer Magnetoresistance set-up, , MRX-01. It is noticed that the resistance of the sample changes when the magnetic field is turned on. The phenomenon, called magnetoresistance, is due to the fact that the drift velocity of all carriers is not same. With the magnetic field on; the Hall voltage V = Eyt = v X H compensates exactly the Lorentz force for carriers with the average velocity; slower carriers will be over compensated and faster one under compensated, resulting in trajectories that are not along the applied field. This results in an effective decrease of the mean free path and hence an increase in resistivity.
Here the above referred symbols are defines as: v = drift velocity; E = applied electric field; t = thickness of the crystal; H = Magnetic field.
>> The set-up consists of the following:
(1) Four Probe arrangement, MRA-01
(2) Sample : Ge Crystal (n-type)
(3) Magnetoresistance Set-up, Model DMR-01
(4) Electromagnet, EMU-50V
(5) Constant Current Power Supply, DPS-50
(6) Digital Gaussmeter, DGM-102/DGM-202
The Set-up complete in all respect.

We offer Hall Effect Experiment, HEX-21 it is designed to give the students first hand experience on techniques for measurement of Hall Coefficient. The resistivity measurements of semiconductors can not reveal whether one or two types of carriers are present; nor distinguish between them. However, this information can be obtained from Hall Coefficient measurements, which are also basic tools for the determination of carrier density and mobilities in conjunction with resistivity measurement.
The Experiment is consists of the following:
1. Hall Probe (Ge Crystal)
2. Hall Effect Set-up (Digital), DHE-21
3. Electromagnet, EMU-75 or EMU-50V
4. Constant Current Power Supply, DPS-175 or DPS-50
5. Digital Gauss meter, DGM-102
The Hall Effect experiment is complete in all respect.

We offer a setup for Study of Hysteresis properties in ferromagnetic samples. A precise knowledge of various magnetic parameters of ferromagnetic substances is an important aspect of magnetic studies. These magnetic properties can be obtained from a magnetic hysteresis loop, which can be obtained by a number of methods. Some of these require samples in ring form, others can be used with films or even rock samples. Ring form samples are not always practical to make while in others, demagnetization effect sometime becomes important.
The present set-up can accept samples of thin wires. The effects of demagnetization, sample diameter and eddy currents have been taken into account.
Besides coercivity, saturation magnetization and retentivity, this set-up can also indicate the number of phases present.
The following magnetic properties of ferromagnetic sample can be studied, with this apparatus.

• Coercivity
• Saturation magnetization
• Retentivity
• Hysteresis loss
• The number of phases present

The set-up is complete in all respect, including long solenoid, its power supply with a panel meter directly calibrated in Gauss, sample holder with a pick-up coil and a set of samples: hard steel, soft iron and nickel (all in wire form). A measuring CRO will however be required.

We offer Apparatus for the Measurement of Susceptibility of Paramagnetic Solution by Quinck’s Tube Method. The force acts on any substance when it is placed in a inhomogeneous magnetic field. This force depends on he susceptibility c, of the material, i.e., on ratio of intensity of magnetization to magnetizing field (I/H). Quantitatively it refers to the extent of induced magnetization in unit field. The force acting on a substance, either of repulsion or attraction, can be measured with the help of an accurate balance in case of solids (Gouy's Method) or with the measurement of rise in level in a narrow capillary in case of liquids. From this measurement, the value of susceptibility can be calculated.

The apparatus consists of the following:

(a) Quinck’s tube, QTT-01, Quink Tube Stand (QTS-01)
(b) Sample: MnSO4.H2O
(c) Electromagnet, EMU-50T / EMU-75T
(d) Constant Current Power Supply, DPS-50 / DPS-175
(e) Digital Gauss-meter, DGM-202
(f) Traveling Microscope, TVM-02

Note: For substances like MnSO4.H2O/ FeCl3, EMU-50T is sufficient, but for substances like water EMU-75T is required.

The experiment is complete in all respect.

We are offering Four Probe Set-up (Research Model), it is one of the standard and most widely used method for the measurement of resistivity. In its useful form, the four probes are collinear. The error due to contact resistance, which is significant in the electrical measurement on semiconductors, is avoided by the use of two extra contacts (probes) between the current contacts.
The experiment is consists of the following:
1. Probes Arrangement, FPA-RM: The probe arrangement is mounted in a suitable stand, which holds the sample plate and RTD (A class) sensor.
2. PID Controlled Oven, PID-200: This is high quality temperature controlled oven suitable for Four Probe Set-up. The oven has been designed for fast heating and cooling rates, which enhances the effectiveness of the controller.
3. Constant Current Source
a) Constant Current Source, CCS-01: This current source is suitable for the resistivity measurement of low to medium resistivity samples such as thin films of metals/alloys and semiconductors such as Ge.
Current Range: 0-20mA & 0-200mA (continuously variable)
Accuracy: ±0.25% of the reading
Resolution: 10μA at 0-20mA range
Load Regulation: ±0.1% for 0 to full load
Line Regulation: ±0.1% for 10% changes
b) Low Current Source, LCS-02: This current source is especially suitable for the resistivity measurement of polymer films, conducting ceramics and Si crystals.
Current Range: 0-2μA, 0-20μA, 0-200μA, 0-2μA
Resolution: 1nA at 0.2μA range
Accuracy: ±0.25% of the reading ±1 digit
Load Regulation: ±0.1% for 0 to full load
4. D.C. Micro-voltmeter, DMV-001
Range: 1mV, 10mV, 100mV, 1V & 10V with 100% over-ranging
Resolution: 1μV
Accuracy: ±0.2%
The experiment is complete in all respect.

We offer precision A.C. Milli-voltmeter very useful in general laboratory and R&D labs. AC Milli-voltmeter is a very versatile instrument of accurate measurement of low signal like microphone outputs, Amplifier frequency response, RMS voltage measurement etc.
Features:

• Measures True RMS Voltage
• Accuracy 1%
• High Input Impedance
• High Stability
• Excellent Linearity

Applications

• Measurement of low signal like microphone outputs e.g. in r.m.s. sound level monitoring
• Amplifier frequency response well beyond audio ranges
• RMS voltage measurement of modulated signals
• Power measurements with external standard resistance

Specifications
Voltage Range: 20mV, 200mV, 2V and 20V
Frequency Range: 10Hz to 200KHz
Input Impedance: 1MΩ shunted by 25pf on all ranges
Accuracy: 1% in the range 10Hz-100KHz; 2% in the range 100KHz-200KHz
Display: 3½ digit, 7 segment LED (12.5mm height) with decimal and overflow indication
Power Supply: 220V ±10%, 50Hz
Weight: 2.5Kg & 3Kg
Accessories: 75cm shielded cable with a coaxial connector at one end and banana plugs on the other end
ACM-103 (Additional Features)
Oscillator Output: 0-300mV continuously variable
Frequency: 1KHz fixed

We offer Linear System Simulator useful for control labs. The set-up offered is a variable configuration simulated system designed for time domain studies of both open loop and closed loop systems. Selection at block diagram level eliminates the need to bother about the details of electronic circuitry and its assembly. The simulator shown includes transfer functions of the form 1/s and 1/(sT+1), a calibrated variable gain K and an error detector.
Highlights

• Time domain study of a Linear System
• Op-amp simulated system for greater accuracy
• Flexible systems configuration
• Additional experiments may be performed

Experiments

• Open and closed loop step response of First Order type-0 system for various values of gain
• Open and closed loop step response of Second Order type-0 and type-1 systems
• Response of third order system
• Steady-State errors for closed loop configuration through triangular wave input.
• The number of experiments possible on the unit is not limited to those suggested above.

Features and Specifications

• Simulated first, second and third order system of type-0 and type-1
• Calibrated variable gain amplifier (Resolution 1:1000)
• Built-in signal sources:

Square wave and Triangular
Frequency: 45-90Hz
Amplitude: 0-2.5V approximately

• Trigger output for perfectly steady display on CRO
• Uncommitted amplifier for phase adjustment
• Provision for disturbance inputs
• Complete in all respect, except a measuring CRO

We offer Linear Variable Differential Transformer useful for control labs. The present experimental unit comprises of a LVDT in a transparent box with lead screw based slow motion displacement, a mm scale for displacement measurement, and main unit consisting of excitation signal source, balanced demodulator, a 3½ digit DVM and necessary power supplies. The signals are provided to the LVDT box through a cable from the main unit.
Highlights

• Large size LVDT for classroom experiment
• Transparent casing for proper viewing
• AC and DC output
• Slow motion displacement

Experiments

• Variation of modulated output with displacement
• Input-Output characteristics
• Determination of linear range and transducer gain

Features and Specifications

• LVDT

Range: ±50mm or total 100mm
Sensitivity: 25mV/cm
Operating frequency: 5KHz±5%

• Displacement measurement on a mm scale with fine motion control
• Carrier source (internal): 5KHz±5%; 1.5V (nominal)
• Built-in 3½ digit DVM for output reading
• IC based balanced demodulator circuit
• IC controlled internal power supplies
• Essential accessory – a CRO

The experiment is complete in all respect, except a CRO.

We offer Study of Integrated Circuit Regulator, Type-723 the following studies can be carried out:
(i) Study of a voltage regulator.
(ii) Study of a current regulator.
The experimental set-up consists of an IC 723 with facilities for convenient connections, an unregulated power supply, voltmeter, an ammeter and all the other components required to perform the experiments.
The set-up is so designed that no high voltage is exposed and hence safe in handling by the students.

We offer Study of Thermoluminescence of F-centers, TLX-02 in Alkali Halide Crystals. A colour centre is a lattice defect that absorbs visible light. These colour centers can be produced by heating the crystal in excess of alkali vapour or by irradiation. The colour centers formed due to trapped electrons or trapped holes can be destroyed (bleached) by illuminating with light or warming. Important information about the colour centers can be obtained from the plot of luminescence intensity vs. temperature, taken at a constant heating rate called glow curve. It may contain one or many glow peaks, depending upon whether there are one or several different kinds of traps.
The experiment consists of the following:
(a) Experimental set-up for creatingvThermoluminescence

(1) Sample: KBr (TLS-KBr) and KCl (TLS-KCl) single crystal
(2) Thermoluminescence Temperature Meter, TL-02
• Digital Thermometer with RTD sensor
• Oven power supply
(3) Sample holder
(4) Thermoluminescence Oven (upto 423K), TLO-02
(5) Black Box, TL-BBx
(b) For measurement of Luminescence Intensity
(1) Photomultiplier tube 931A, TL-PMT
(2) PMT Housing with biasing circuit and connecting coaxial cables, TL-PMH
(3) High Voltage Power supply, EHT-11
(4) Digital Nanoammeter, DNM-121
Complete in all respect, only X-ray facilities are required to create F-centers in the crystal.

We offer Study of Basic Operational Amplifier, TYPE-741, the following studies can be carried out:

1. Working of the basic circuit.
2. Measurement of bias and offset currents.
3. Study of inverting and non-inverting configurations.
4. Study of Amplifier drift.

The set-up is so designed that no high voltage is exposed and hence safe in handling by the students.

We offer Semiconductors Diode Characteristics, SDC-02 with this following features:
• Forward and reverse characteristics of Ge, Si diodes and LEDs
• Study of Zener diode characteristics
• CRO display of forward and reverse characteristics.
The set-up is provided with a booklet which contains its theory of operation, description, suggestions and discussion of the experiments that my be performed with it.
The circuit is all electronic using transformer and electronic components Viz. IC’s, transistors, capacitors and resistance etc. The whole circuit operates on 200V ± 10% 50 Hz AC and mounted in a metallic cabinet which is grounded through the grounding lead of power connector and hence safe towards electrical hazard, if any.

We offer Study of Hybrid Parameters of A Transistor, HP-01 the following studies can be carried out with this set-up:

1. Study of h₁₁ parameter (input impendance parameter).
2. Study of h₂₂ parameter (output admittance parameter).
3. Study of h₂₁ parameter (forward current transfer ratio).
4. Study of h₁₂ parameter (reverse voltage feedback ratio).

The experimental set-up is provided with a built-in power supplied and is complete.
The set-up is so designed that no high voltage is exposed and hence safe in handling by the students.

The Hall voltage for p-carriers has opposite sign from that for n-carriers. Therefore if a semiconductor with p-type doping is gradually heated up, more and more electrons from its valence band will go to conduction band. As a result hall voltage would fall rapidly with temperature and even become zero or change sign. At the point of zero Hall Coefficient, it is possible to determine the ratio of mobilities b=me/mh. The Hall coefficient inversion is a characteristic of only p-type semiconductors.
The set-up consists of the following:

1. Hall Probe (Ge: p-type), HPP-22
Ge single crystal with four spring type pressure contacts is mounted on a glass-epoxy strip. Leads are provided for connections with the current source and Hall voltage measuring devices.

Oven
It is a small oven which could be easily mounted over the crystal or removed if required.
Temperature Sensor
Chromel-Alumel thermocouple with its junction at a distance of 1mm from the crystal.
2. Hall Effect Set-up :DHE-22
The set-up, DHE-22 consists of two sub set-ups, each consisting of further two units.

Measurement of Probe Current & Hall Voltage
This unit consists of digital milli voltmeter and constant current power supply. The Hall voltage and probe current can be read on the same digital panel meter through a selector switch.
Measurement of Thermo emf and Heater current
The unit consists of a digital milli voltmeter and constant current power supply. The thermo emf of thermocouple and heater current can be read on the same DPM through a selector switch.
5. Electromagnet, EMU-50V
6. Constant Current Power Supply, DPS-50
7. Digital Gauss-meter, DGM-202/ DGM-102
The experiment is complete in all respect.

Electromagnet & power supply EMU-50 & DPS-50.
We are offering Electromagnet & Power Supply. These electromagnets have the most widely used ‘U’ shaped soft iron yoke. The soft iron is of a special quality, structurally uniform, well machined and finished to meet the rigid standards.
The air-gap is continuously variable with two way knobbed wheel screw adjusting system. EMU-50V is supplied with flat pole pieces and EMU-50T is supplied with tappered pole pieces.

Specifications
Pole Pieces: Φ50mm diameter flat in EMU-50
: Φ50mm tapered to 20 mm in EMU-50T
Field: EMU-50: 7.5KG, at 10mm airgap
: EMU-50T: 9.5KG at 10mm airgap
Energizing Coils: Two, each with a resistance of about 3W
Power Requirement: 0-30Vdc, 4A, if coils are connected in series
DPS-50 is an inexpensive and high performance constant current source suitable for small and medium sized electromagnets. Although the equipment is designed for the Electromagnet, Model: EMU-50, it can be used satisfactorily with any other electromagnet provided the coil resistance does not exceed 6Ω.

Specifications
Current Range: Smoothly adjustable from 0–4A
Load Regulation: 0.1% for load variation from 0 to max.
Line Regulation: 0.1% for ±10% mains variation
Display: 3½ digit, 7 segment LED DPM
Power: 220V ±10%, 50Hz
Weight: 9Kg
Dimensions: 335mm X 305mm X 155mm

We offer D.C. Speed Control System useful for control labs. The present unit, built around a small permanent magnet d.c. motor, is designed to bring out the salient features of such a system. Facilities are available to directly measure the principal performance features of the speed control system, viz., steady state error and load disturbance rejection, as a function of the forward path gain. In addition, the experimental work involves the determination of the motor transfer function and the characteristics of the tachogenerator.

Highlights of Equipment:

• Closed loop motor speed control with eddy current brake
• Compact system-no mechanical hassles
• Optoelectronic speed sensor
• Digital display of speed on the panel

Experiments:

• Effect of loading on the speed of the motor in the open loop
• Steady state error variation with forward gain
• System time constant variation with forward gain
• Effect of forward gain on disturbance rejection
• Determination of the motor transfer function and tachometer characteristics

Features and Specifications

• Speed control of a 12V, 4W permanent magnet d.c. motor
• Speed range: 0 to 3000 rpm (typical)
• Opto Interrupter based speed sensing
• 4-digit speed display in rpm
• Electronic tachogenerator for feedback
• Separate unit for motor in a see-through cabinet
• Smooth, non-contact eddy current brake for loading
• Built-in 3½ digit DVM for signal measurements
• Built-in IC regulated internal power supply
• Supporting literature and patch cords included
• Essential accessory – a CRO

The experiment is complete in all respect, except a CRO.

We offer Apparatus for Measurement of Susceptibility of Paramagnetic Solids by Gouy’s Method in this, the solid sample in the form of a long cylinder (area of cross section A) is hung from the pan of a balance and is placed such that one end of the sample is between the pole-pieces of the magnet (field H ) and the other one is outside the field. The force exerted on the sample by the inhomogeneous magnetic field is obtained by measuring the apparent change in the mass of the sample.
The set up consists of the following:
(a) Scientific Balance, KSB-07
Capacity: 200 gms
Sensitivity: 1/10 mg. by vernier
Beam: Hard Bronze/ Brass
Arrestment: Circular, falling away type
Air Damping: Very quick and positive, beam coming to rest in 2-3 sec

(b) Sample in the form of a long rod:
Set of 4 samples, 2 each of Ebonite and Wood
(c) Electromagnet, Model EMU-75T
Pole Pieces: 75mm tapered to 25mm
Mag. Field: 20KG at 6mm air-gap
Energizing Coils: Two of approx. 13W each
Power: 0-90Vdc, 3A, for coils in series
0-45Vdc, 6A, for coils in parallel
(d) Constant Current Power Supply, Model DPS-175

(e) Gauss-meter, Model DGM-202 or DGM-102
The experiment is complete in all respect.

We offer Four Probe Method it is one of the standard and most widely used method for the measurement of resistivity. In its useful form, the four probes are collinear. The error due to contact resistance, which is significant in the electrical measurement on semiconductors, is avoided by the use of two extra contacts (probes) between the current contacts.
Features

• Easy resistivity mapping of large sample
• 2-way movement with vernier scales (0.01mm)
• Spring loaded contacts for firm connections

Experiment consists of the following:
1. Probes Arrangement, FPA-01
It has four individually spring loaded probes. The probes are collinear and equally spaced. The probes are mounted in a teflon bush, which ensure a good electrical insulation between the probes. A teflon spacer near the tips is also provided to keep the probes at equal distance. The probe arrangement is mounted in a tube, which also provide leads for connections to Constant Current Power Supply and D.C. Microvoltmeter. The tube containing four probes is mounted on a traveling microscope type system, scales and verniers are made of stainless steels with following specification:

• Horizontal: 20 cm least count 0.001 cm
• Material: 6 cm least count 0.001 cm
• Vertical: 15 cm least count 0.001 cm
• The bed is of heavy casting, thoroughly aged and machined, is fitted with leveling screws. A large platform is provided for fixing the sample.

2. Constant Current Source
a) Constant Current Source, Model : CCS-01 (for low resistivity samples)
b) Low Current Source, Model : LCS-02 (for high resistivity sample)
3. D.C. Microvoltmeter, DMV-001
The experiment complete in all respects.