Dual Adjustable Power Supply Circuit

This is the circuit diagram of a dual adjustable power supply using IC’s LM 317 & LM 337.LM 317 is able to deliver a maximum of 1.5 A at a range of 1.2 V to +30V .LM 337 is the negative complement of LM317.They also have a built in short circuit protection.

Here the circuit is wired to produce a dual adjustable output of ( +15 , 0 , -15 ).The capacitors C1 to C8 provides filtering and ripple rejection.Resistors R1 & R2 controls output of LM 317.Resistors R3 & R4 controls the output of LM 337 .R1 and R4 can be turned to vary the positive and negative voltages.This circuit is a must on an electronic hobbyists workbench.

Circuit Diagram :-

Micowave Engineering May June 2011 (BTE Delhi)

Question of Microwave Engineering (May/June 2011) is Submitted by Preetam Singh. We would like to thanks him for helping the students !!!

 

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15W Audio Amplifier Circuit (Class B)

The circuit shown here is of a simple Class-B audio amplifier based on op-amp TL082, transistors TIP41 and TIP42. LM833 is a dual op-amp with high slew rate and low distortion particularly designed for audio applications. This audio amplifier circuit can deliver 15 watt audio output into an 8 ohm speaker at +12/-12V DC dual supply.

Both op-amps in the IC are used here. IC1a is wired as a buffer and capacitor C3 does the job of input DC decoupling. Ic1b is wired in the inverting mode and it provides negative feedback. Complementary power transistors TIP41 and TIP42 are wired in the Class B push pull scheme and they drives the loud speaker. Diode D1 provides 0.7V bias voltage for the push pull pair and capacitor C2 protects the 0.7V bias voltage across D1 from heavy voltage swings at the IC1b’s output.

 Circuit Diagram of 15watt Class B Audio Amp :-

EDC III (May / June 2011) Question Paper

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Digital voltmeter using ICL7107

Description.

The circuit given here is of a very useful and accurate digital voltmeter with LED display using the ICL7107 from Intersil. The ICL7107 is a high performance, low power, 3.5 digit analog to digital converter. The IC includes internal circuitry for seven segment decoders, display drivers, reference voltage source and a clock. The power dissipation is less than 10mW and the display stability is very high.

Funcation Genrator Circuitusing IC 8038

Description.

The ICL8038 is a function generator chip, capable of generating triangular, square , sine, pulse and sawtooth waveforms. From these sine, square & triangular wave forms can be made simultaneously.There is an option to control the parameters like frequency,duty cycle and distortion of these functions.This is the best function generator circuit for a beginner to start with and is of course a must on the work bench of an electronics hobbyist.The circuit here is designed to produce waveforms from 20Hz to 20 kHz.The ICL 8038 has to be operated from a dual power supply.

Circuit Diagram & Part list