Bhushan & Bhushan

This Module of Active Filters contains 12 Filters.Op Amps have been used to design the active RC circuits which are used as filters .A filter may be described in terms of the basic function of the filter.The following filters are there:

The equipment produces amplitude modulation of an internally generated RF carrier by an external audio signal or a locally available DC signal. Demodulation can be done by two different types of detectors.

Modulator Carrier Freq : 100KHz

Oscillator : Built-in.

Types of Amp. : 1.DSB with Carrier Modulation

2.DSBS ( Supressed Carrier )

T ypes of Detector : 1. Diode Type w/ Variable RC (1mS- 10mS)

2. Product / Square Law detector, local freq. 500 KHz.

Local oscillator : Can be locked in phase or can run out of lock w.r.t 500 KHz Carrier Osc.

Spectrum Analyser : Built-in for measurement & detection of sidebands

Analog Trainer model 700 is a low cost trainer ideally suited to train and familiarize students with Analog Computation. Differential equations upto the sixth order can be solved with an accuracy of better than 1%. It has the following :-

Op. Amplifier : 10 with gain of 1,00,000 typical

Indicating Meter : Ranges + 1V, +3V, + 10V & +30V

Integrator : Six

Co-efficient : One ten turn Helical pot, ten single turn potentiometers. setting Pots

Mode of Operation : Manual and Repetitive mode.

Power Supplies : +15V (Main) & +10V (Ref.)

Options Available : Analog Memory, Multiplier, Variable Function Generator, Nonlinearity simulator can simulate limiting, dead band and hysteresis/backlash.

Capacitive and Resistive type angular position sensing system with associated Mechanical Jig, Capacitor, Oscillator & Discriminator.

CapacitiveSensor : Dual Type ,22 to 220pF

Resistive Sensor : Multiturn,10K

Oscillator : 100KHz ,Nominal

Discriminator : Phase locked loop based

Operating Power : 230 V +10%, 50Hz

Display : 3 1/2digits LED

Range : 0 to 900C approx.

Resolution : 10

Superconductivity was discovered in 1911 and has since then developed into and important area of research with fantastic possible applications such as, frictionless bearing, high speed transport, and long lasting energy sources. ROMTEK Super Conductivity Apparatus has been developed to familiarize students with this unique phenomenon and to conduct experiments such as observation of Meisner effect, measurement of critical temperature, measurement of resistivity, measurement of critical current density, measurement of critical magnetic field and observation of reverse AC Josephson effect. The equipment contains the necessary electronics for measurements in a single console and enables the experiments to be performed quickly and conveniently.

0.01% Line & Load Regulation, 1mV ripple, CV / CC Characteristics, autotracking/ independent modes, remote sensing, SCR crowbar protection, fully protected, ruggedly built, rated for 0^oC - 50^oC; upto 95% RH, compact, lightweight, elegantly finished, continuous operation rating, choice of digital or analog meters.

This module is designed to familiarize the student with this type of Modulation & Demodulation.The modulator can be switched to work as DM or SDM.

Delta / Sigma Delta : Depending on front panel

Modulator switch setting.

Frequency : 20KHz or 100KHz.

Input Signals : a) Built - in +5V to -5V DC

b) External audio signal

Demodulator : Can be set to work as

Delta / Sigma Delta

Demodulator gain : Ajustable from 1 to 2

Error Amplifier : High Quality.Measures

Quantisation Error.

Comparator O/P,Pulse Generator,Adder & Integrator brought out for monitoring waveforms.

ROMTEK Discrete Component Trainer is provided with practically all the discrete components used in Electronics. It has built-in short circuit protected power supplies +5V,+12V,and variable 0-20V & assorted components resistors, capacitors, inductors, diodes, Zener diode, Varicapdiode, SCR, Diac, Triac, VDR, LDR, Photo diode, LED's, transistors, FET's, UJT's, matched transistor pair, potentiometers, transformer, speaker, relay, etc., all terminated on high quality banana sockets. A meter and switches & indicators for setting and monitoring logic levels are also provided. A comprehensive manual is provided..

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Romtek Model 707 Kit is based on the Internationally accepted practronix concept. The Kit consists of one basic instrument containing power supplies, oscillator from 1Hz to 1KHz, a set of 8 masks, 100 plug-in components and a comprehensive instruction manual. With the help of this kit it is possible to cover basic electronics course in Industrial Training Institutes, Degree Colleges & Vocational Schools. It can also cover courses in various schools & short term courses run by private institutions. Such a wide spectrum of educational levels is possible with this kit using the same basic instrument & using different masks & different set of components. Model 707 permits more than 60 different experiments to be performed in basic electronics using solderless components.

Romtek Enhanced Superconductivity Apparatus has been introduced after seeing the popular response to our Basic Superconductivity Apparatus introduced 3 years back. Thanks to the introduction of the apparatus, more & more students are experimenting with superconductivity and who knows, India may become the place of a breakthrough in this technology. The Suspension / Levitation effect showing Suspension of superconductor below a Neodymium magnet was accidently discovered by Huang & Peter of Lockheed & NASA respectively. Romtek has included a special Enhanced Flux Pinning Disk (EFP) in the Kit to show this effect. The US Navy designed an experiment called SMES (Superconductive Magnetic Energy Storage), whereby a current was induced in a superconductivity ring & shown to decay with a life time of the order by 10 ²³ years! This experiment can be performed in the Romtek Enhanced Superconductivity Apparatus with material provided in here. Magnetic Susceptibility experiment is based on the expulsion of magnetic field by superconductor. Materials provided in the kit enable measurement of critical temperature based on susceptibility measurements as also computation of magnetic susceptibility of superconductor. These measurements are more accurate than those based on Meisner Effect.

This module is designed to demonstrate the concepts involved in Frequency Modulation and Demodulation.

Types of Detector : 1.Diode Type with variable RC (1mS,10mS) 2.Product/Square Law detector; local freq 100KHz.

Local oscillator : Can be locked in phase or can run out of lock w.r.t. 100KHz

Modulators : 2 with built-in Carrier Oscillators

Carrier Oscillators : 2 Nos. having different frequencies

Signal I/P : AC modulating signals or local DC signal

Experiment on adjacent channel rejection : Can be performed as 2 modulators are given,serving as two transmitters

Types of detectors : 1. Foster Seeley Detector 2. Ratio Detector.

Model 800 range of Function Generators are low cost instruments for the customer looking for the best price-performance ratio. All the models introduced by us offer high quality sine, square and triangle waveforms with DC off set, sweep frequency, VCO facility, frequency modulation, TTL trigger output, push button selection of ranges, digital display of frequency and multiturn frequency control.The specifications are as given below:

Frequency Range : a) Model 800 / 100K : 0.1Hz to 100 KHz.

b) Model 800 / 1M : 1 Hz to 1 MHz.

c) Model 800 / 2M : 2 Hz to 2 MHz.

d) Model 800 / 3M : 3 Hz to 3 MHz.

e) Model 800 / 5M: 5 Hz to 5 MHz

f) Model 800 / 10M: 10Hz to 10 Mhz

Waveforms : Sine, Square and Triangle.

Output Magnitude : 0-20 V P-P, variable.

Trigger Output : TTL output given.

VCO/FM/Sweep : Facility provided.

Display : 3½ Digit LED/LCD digital display of frequency.

Frequency Control : Multiturn Helipot to provide extremely smooth control of frequency.

Type of Controls : Push Button Selection.

Instrument works on 230 V/115V+ 10%, AC Single Phase

(110V operation provided on international models).

Measures 6"x 8"x 2"

Circuit Schematic Printed on front with circuit etched in copper and components soldered on reverse.

Plastic see through back panel enables circuit viewing / tracing

Over 200 boards cover full course in basic electronics

Boards based on standard text book by TTI Chandigarh

Banana terminal for I/P, O/P and to monitor waveforms at different points

Romtek Instrumentation Trainer Model 890 provides the means to teach the students various Instrumention techniques. It is provided with various tranducers and associated Jigs, Rigs and Fixtures such as Linear Transducer Test Rig, Optical Rig and Thermal Rig etc. The instrument is beautifully made with all the transducers and assiciated Jigs visible from the front itself for a clear understanding.

Inductive and Resistive position sensing system ,based on LVDT with excitation oscillator, Amplifier and Phase Sensitive Detector.

Range : 0 to + 5 mm

Accuracy : +1% FSD

Micrometer : Built - In

Excitation : 1 to 4 KHz

Display : 3 1/2 digits, LED

Operating Power : 230 V+10%, 50Hz

Micrometer Range : 25mm

Micrometer resolution : 0.01m

Model 209 is an automatic/manual tester for Operational Amplifiers, Comparators, Timers, Voltage Regulators and Phase Locked Loops. It consists of a main frame which has got power supplies and metering facilities. It has a set of plug-ins, one plug-in catering to one family of linear IC's .It's automatic operation makes it ideal for purchase inspection. Its manual operation makes it ideal for R & D applications, where each parameter can be tested in detail.Another application of the equipment is to use the equipment for demonstrating linear IC's to students.

ROMTEK Linear Circuit trainer is a versatile and self contained equipment. It has the following linear IC's: 741, 308, TL061, 723, 733, 810, 710, 7805, 555 & 565. Two variable built in short circuit protected power supplies of 0 to +12V and 0 to -12 are provided. Discrete components like 62 resistors of 100E to 1M, 22 capacitors of 100pF to 100mF, and potentiometers are also there. All the experiments in linear electronics can be performed very easily. A detailed instruction manual having nearly 50 experiments is provided with the equipment.

Logic Lab Model 825 is a beautiful, handy, breadboarding Lab with built-in two breadboards,Logic Hi - Lo indicators,Clock,Pulser , Power Supply,and, 7 Segment LED Display with decoder. The unit has a slanting panel. It is ideal for budget consious users.The breadboard can easily be detached, permitting a number of experiments to be wired,and stored for use at different times.

This model is similar to 15035TTTI ,except for the following differences :

Breadboards : Four breadboards 175 mm long, 2560 tie points, 800

distribution points, Ni plated brass contacts accepts 24 SWG hook up wires. Can accomodate DIP IC's.

Logic Switches : 16 Nos. to generate Hi - Lo signals.

Logic Indicators : 16 Nos. LED indicates Hi - lo.

Display : 7 Segment, LED, with built - in decoder(7447 )IC -4 Nos.

Built-in P. Supply : Regulated +5V/1A,+15V/350mA,DC.

This model consists of a set of logic gates, flip-flops, logic indicators, logic switches, pulsers, clock and 7 segments display. The front panel of the equipment is printed on the printed board itsef on which the circuit and the electronics is etched on its reverse. The sockets used for the patch cords are also soldered. The full assmbly is on the printed circuit and there is no wiring resulting in absence of loose contacts Detailed manual with experiments.

Logic Mini Lab Model 818 is a beautiful, handy,breadboarding Lab with built-in single breadboard 175mm long,Logic Hi - Lo switches , Logic Hi - Lo indicators,Clock,Pulser , Power Supply,and, 7 Segment LED Display with decoder. The unit has a slanting panel It is ideal for budget consious users.

Model 750 DLI has been designed to cover the syllabus of Digital Electronics as applicable to Diploma courses in the country. The equipment consists of +5V and +15 V supplies, clock, Hi Lo switches,LED Indicators,7 segment displays and several integrated Circuits such as Gates, Flip Flops,counters,shift Registers,coders and Encoders, Buffers, A-D and D-A converters, expanders, Schmitt Triggers etc. On the back of the panel, the electronic circuit is wired. The sockets used for insertion of the patch cords are also soldered on the PCB. This has resulted in a very high degree of reliability.

Light measurement and light sensing device system with Photodiode, Phototransistor, LDR and associated arrangements for variable intensity light and amplifier.

Filters are of many types & in Passive filters we deal in T and P types of networks.We have filters of low pass, high pass,band stop and crystal type.We also have filters called prototypes,m derived & m derived terminating half sections.

After designing the PCB,it is required to expose it after coating it with chemicals etc.This set consists of :

a) UV Exposure machine,

b) PCB Chemicals set required for all processes such as Photo exposure, Developing, Drying , Coating etc.

c) All small tools such as high qualitytweezers,brushes, cutter, sponges, enamel tray, syringes, brushes, exposure frame etc.

This consists of the design and material for designing 60 PCB's for a class of 30 students.PCB Design Kit consists of circuit scematics & the following :

a) Components such as Transistors, Diodes, IC's for dimensional purposes,.........50 Nos.

b) Copper Clad sheets cut to 6"x4" size........60 Nos.

c) PCB Drafting Stickers,Tapes................... 2mm,3mm

IC Pads...................8 Pins

Doughnut Pads.................. 5mm

Transistors pads etc. to make..................60 PCB's

d) Plastic films cut to 7"x5" size...................60 Pcs.

It is required to etch the design after exposing,for this the set consists of the following:

a) Etching Bath/Chamber.

b)Etching Trays etc.

c) Chemicals required for etching,tinning etc.

d)Small tools required ,sponges, brushes, gloves etc.

e) Water bath etc. for washing after etching.

This consists of the equipment and material used to design the PCB's and then Inspecting it after the PCB is made.It consists of the following :

a) Illumunated Work Station.........................1No.

b)Illuminated Magnifier PCB Checker............1No.

(Magnifies the job kept under it to 2 times its size, two and a half inch area is magnified)

c) 10x Magnifier(Magnifies 10 times).............1No.

d) Hole Dia checker,Checks the dia of ..........1No.

component leads from 0.5mm to 4mm.

PID Controller Trainers, Model 8972 is analog based.The analog Controller has inputs from potentiometers and moving coil meters to display the inputs and outputs.The controllers have got 4- 20 mA/0-5V input and output, proportionate band from 2 to 500%, integral action time of 0.03 repeats per minute and dervative action time 0 to 10 minutes.The set point is 10 to 90% of output in both the cases.

This is an Analog Simulator designed to familiarise students with a wide variety of linear and non-linear processes and the application of proportional, integral, derivative, two steps, three steps controllers. The equipment teaches hardware such as PID controllers, non-linearity (limiting, dead space, back lash), transmitters (current to voltage and voltage to current) and terminology such as detecting element, correcting element and supply load disturbance and motor element etc. Practicals include setting up to a process with different facilities and transfor function and study of transfer function of the process.The equipment is essential for students of process control and instrumentation.

The process in this trainer consists of temperature control of a moving stream of air. A blower blows air into an insulated pipe. Heater is provided to raise the temperature. Temperature sensors are provided along the length of the tube. The heater can be controlled by a built-in amplifier. A PID Controller is built into the equipment. The blower speed can also be adjusted. Using these, a closed loop temperature system is established and verious types of controls such as anticipatory , 0 error, On - Off type, etc. can be established.The open and closed loop transfer functions and response of the process to different variable can therefore, be studied.

Romtek Basic Hydrogen Fuel Cell Apparatus demonstrates & enables detailed experiments on harnessing renewable energy to power the cars of the future. It incorporates multidisciplinary technologies and is useful to educators & experimenters in Physics & Chemistry; Electronics & Mechanical Engg. & Non-Conventional Energy Sciences.

How it Works

The apparatus uses a PEM (Polymer Electrolyte Membrane) reversible, bi-modal fuel cell, a solar panel, a dc motor driven, scaled down automobile, a winch attachment for lifting a small mass & electronics control module.

In mode One, fuel Cell works as Electrolyser, accepting electricity obtained from sunlight, to electrolyse distilled water to Hydrogen & Oxygen, which is then stored in a graduated container. In mode 2, the Fuel Cell accepts the stored Hydrogen & Oxygen as input and generates electricity. The generated electricity drives a dc motor, which drives the model 4-wheeled vehicle. Provision is there for the motor to lift a known small mass using a winch attachment to directly measure mechanical work done. A block diagram illustrates the processes:

Rotational speed measurement system with built- in motor, sensors of optical and magnetic type and electronic counter. Demonstrates Photoreflective and Photointerruptive type sensors in addition to magnetic sensing.

FEATURES

• Automatic dusk to dawn operation

• Energy-packed to work for 4 continuous days even in the absence of sufficient light

• High Power LED with luminous efficiency of 100lm/watt and long life upto 50,000 hrs

• Galvanised steel pole that resists rusting

Strain gauge sensor with Cantilever beam system ,to show working of strain guage and measurement thereof with associated mechanical arrangements and electronic circuits.

Range : 0.500 millistrains

Accuracy : 10 microstrains

Strain Gauge : 120ohms

Strain gauge type : Foil type

Micrometer travel : 25mm

Micrometer Accuracy : 0.01mm

Bridge Balancing : Coarse and fine

Display : 3 1/2 digits, LED

Operating Power : 230 V + 10%,AC 50H

Temperature Sensor System with Thermocouple, Platinum Resistance Thermometer & Thermistor, and associated Amplifiers, Bridge, Cold Junction Compensation Circuit , Heat Source & Heat Jig to generate different temperatures.

This module is designed to demonstrate propogation,attenuation and reflection along transmission line with coaxial line being used to illustrate the subject.

Pulse Generator ( Transmitter )

Transmission Line

Characteristic : 75 W and 50 W

impedance

Length : 40 Metres

No. of Sections : Four

I/P & O/P of : BNC Sockets

Tx. lines on

A microwave test bench is an assembly of various microwave components, held together by Nuts & Bolts. It consists of a microwave source (Oscillator) at one end. The waves generated are led down by a wave guide through various components, so that the student can observe the propagation of waves, and their interaction and/or processing by various components.

This bench consists of the following components :

ferrite based.Made out of circulator by terminating

one of its three ports into matched loads.

Frequency : 1MHz wide within X-Band

Isolation : 20dB Typical

Frequency counter model 530 is a high performance 8 digit LED Counter / Timer having high sensitivity, automatically placed decimal point, unit indicator, controlled crystal indicator. It has a 3 position attenuator and permits counting and timing measurements over a wide range.

Freq. Range : 1Hz to 10MHz

Sensitivity : 40mV rms for Sine Wave, 100mV p-p for pulsed wave with min.pulse width of 100nS

Accuracy : +1digit+ time base error

Time period measurement : 400nSec to 10 Sec

Time interval measurement : 100nSec to 10 Sec

Display : 8 Digit

Frequency counter model 548 is a high performance 8 digit LED Counter having high sensitivity, automatically placed decimal point, unit indicator, controlled crystal indicator etc.

Freq. Range : 20Hz to 1200 MHz

Sensitivity : 10mV rms

Accuracy : +1 Count + time base error

Time period resolution : 100nSec

Operating Conditions : 230Volts + 10%,50Hz single phase

Display : 8 Digit LED Display

Frequency counter model 539 is a high performance 8 digit LED Counter / Timer having high sensitivity, automatically placed decimal point, unit indicator, controlled crystal indicator etc. It has a 3 position attenuator and permits counting and timing measurements over a wide range.

Freq. Range : 1Hz to 50MHz

Sensitivity : 40mV rms for Sine Wave, 100mV p-p for pulsed wave with min.pulse width of 100nS

Accuracy : +1digit + time base error

Time period measurement : 400nSec to 10 Sec

Time interval measurement : 100nSec to 10 Sec

Display : 8 Digit

Romtek introduces an all-in-one Component Tester to take care of discrete component testing. In a single handy equipment, the tester can handle diodes, LED's, transistors, resistances, inductances and capacitors. The equipment permits great accuracy for all your components testing. The display is digital, 3 1/2 digit LED (0.3" height).

Inductance Measurement : Upto 20H

Resistance Measurement : Upto 20MW

Capacitance Measurement : Upto20mF

Diode Testing : For forward & reverse voltage

Zener diode testing : Determines Zener voltage

LED Testing : Done

Transistor Testing : Determination of NPN/PNP type

Transistor good/bad : Done for PNP&NPN

Transistor Measurement : Gain & Leakage

Transistor Characteristics : Plotting on external CRO for ALL modes(Common base, emitter & collector)

Transistor `h' parameters : Can be done

Measurement of `Q' : Can be done.

After Etching the design holes are to be drilled for insertion of components.After checking the diameter of the hole to be drilled by using the hole dia checker provided earlier,one can drill the holes. This station consists of the following:

a) High Speed motorised precision drilling machine.

b)Small tools such as drill bits of various sizes,tweezers, cutters ,pliers etc.

c) Stand for the drill machine etc.

With the increasing concern for pollution and industrial safety, we have brought out a range of toxic and flammable gas detectors. A range of models cover gas detectors, single channel gas detectors, four channel gas detectors, and 24 channel rack mounted gas detection systems. A large number of gases can be detected by this system. Gases include Methane, Acytylene, Gasoline and Kerosene vapours, several hydrocarbons, ammonia etc.

Waveform  Synthesiser Cum Analyzer ( Fourier  Concept  Demonstrator )

In communication one always comes across signals which are non sinusoidal and complex. Fourier analysis tells us that any complex signal consists of fundamental and a set of even and odd harmonics.

Synthesis of waveform:

Done by selecting 16 points on waveform

Slide Pots : 16, for selecting shape of waveform,

Knobs set to form pattern

resemblling waveform

Magn. Spectrum : Can be plotted.

The Error Probability Trainer brings out the concepts of noise in communication channel from statistical point of view. All Communications systems are to be designed so that the probability of error is minimised. A generator produces pseudo random binary sequence which acts as a signal. A random noise generator of variable amplitude is there. The signal and the noise are added to make the transmitted signal. The receiver correctly detects the binary sequence present in the mixture of the signal and noise,and the counter indicates the error count.

Analog & Digital Lab ia self contained equipment, designed to perform practicals on all digital and linear circuits. It also permits breadboarding of prototype circuits, no soldering is required. In addition to regulated power supplies.

Education institutions wishing to familiarize students with PCB techniques are forced to buy the expensive machines available in the market .Romtek has long been familiar with educational requirements and budgetry constraints . Accordingly a PCB Equipments set up is introduced which is an assemblage of tools, chemicals,jigs, fixtures and small equipments which has a do-it-yourself approach.This set up takes the students from the circuit schematic stage to final PCB.

This trainer is designed to teach the basic concepts of Pulse Code Modulation. This is a self contained unit with a PCM modulator & demodulator.

Signal I/P : Audio signal or local DC from -8V to +8V analog signal

Pulse Code O/P : 3 Bits or 4 Bits; selectable

Bit Rate : Variable from 4 KHz to 40 KHz

Demodulator : Built - in

Low Pass Filter : Can be introduced by a switch in the demodulated O/P signal

Built-in Difference Amplifier : Given; demod.O/P can be compared to modulator I/P

Quantization error measurement ckts : Effect of changing bit rate & changing coding from 3 bit to 4 bit can be seen on these

Synchronizing pulse O/P : 2V p-p, 0.1mS

In digital communications, sampling of the Analog signals is done at discrete intervals.Discrete samples of different signals are time multiplexed on a single wire.

Sampler : a) Frequency - 2 to 20 KHz,

b) Pulse width - 10 mS to 150 mSec

c) LED indicator if pulse width

exceeds 1/4 of time period of

sampling freq.

I/P sockets: 2 I/P for sampling & multiplexing.

Speech simulating : a) Facility for On/Off signal

b) Amplitude - 2V p-p,

c) Band width-upto 3KHz

Demultiplexer : Synchronous type - 2 O/Ps.

Low pass filters : 2 Nos.,cut off in audio range,

removes sampling spikes from demultiplexer O/P

All important signal are brought on the front panel