Diagram IR Remote Control Circuit using Op amp 741

IR circuit is called Infrared Circuit. Remote controlsare
very much popular now-a-days. It is specially called cordless circuit.
This circuit is very simple and low cost cordless remote control circuit
which is based on infrared   rays.

Figure 1 shows thetransmitter circuit. The transmitter produces infrared rays and that can be easily transmitted up to 4 meters with a special convex lens and a twin LEDarrangements.

Figure 2 shows thereceiver circuit. Op amp IC1-741 generates high frequency squire wave which provides the gate pulses for SCR1. IC1’s output current flows through  SRC1 and it is conducting current and enables the LED to emits infrared rays. The output frequency of Op amp IC1 depends on the variable resistor VR1, which in turns varies the output radiations of the LED.

When IR rays
fall on the photo-transistor T1 of the receiver, then base of the
photo-transistor’s base produces charge carriers at a rate depending on
the rate of arrival of incident radiationsat
the pn junction of the transistor. Then the resulting emitter voltage
is amplified by Op amp IC-2 . The amplified signal is rectified by D2.
Finally the amplified signal is to drive the relay.

Parts List:

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Build a Low Noise And Drift Composite Amp Wiring diagram Schematic

How to Build a Low Noise And Drift Composite Amp Circuit Diagram. This schema offers the best of both worlds. It can be combined with a low input offset voltage and drift without degrading the overall system`s dynamic performance. 

 Low Noise And Drift Composite Amp Circuit Diagram

Compared to a standalone FET input operational amplifier, the composite amplifier schema exhibits a 20-fold improvement in voltage offset and drift. In this schema arrangement, A1 is a highspeed FET input op amp with a closed-loop gain of 100 (the source impedance was arbitrarily chosen to be 100 kfl). A2 is a Super Beta bipolar input op amp. It has good dc characteristics, biFET-level input bias current, and low noise. A2 monitors the voltage at the input of A1 and injects current to Al`s null pins. This forces A1 to have the input properties of a bipolar amplifier while maintaining its bandwidth and low-input-bias-current noise.

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Vocal Adaptor for Bass Guitar Amp

These days, music is a major hobby for the young and not-so-young. Lots of people  enjoy  making  music,  and  more  and  more dream of showing off their talents on stage. But one of the major problems often encountered is the cost of musical equipment. How many amateur music groups sing  through an amp borrowed from a guitarist or bass player?
This is where the technical problems arise not in terms of the .25” (6.3 mm)  jack, but in terms of the sound quality (the words  are barely understandable) and volume (the amp  seems to produce fewer decibels than for a guitar). What’s more, unpredictable feedback may cause damage to the speakers and is very unpleasant on the ear. This cheap little  easy-to-build project can help solve these technical  problems.

Vocal Adaptor for Bass Guitar Amp Circuit Diagram

A guitar (or bass guitar) amplifier is designed first and foremost to reproduce the sound of the guitar or bass as faithfully as  possible. The frequency response of the amp doesn’t need to be as wide or as flat as in hi-fi (particularly at the high end), and so this sort of amplifier won’t permit faithful reproduction of the voice. If you build an adaptor to compensate for the amp’s limited frequency response by amplifying in advance the frequencies that are  then attenuated by the amp, it’s possible to  improve the quality of the vocal sound. That’s  just what this schema attempts to do.
The adaptor is built around the TL072CN low-noise dual FET op-amp, which offers good value for money. The NE5532 can be used with almost the same sound quality, but at (slightly) higher cost. The schema breaks  down into two stages. The first stage is used to match the input impedance and amplify the microphone signal. For a small 15 W guitar or bass amplifier, the achievable gain is  about 100 (gain = P1/R1). For more powerful amplifiers, the gain can be reduced to  around 50 by adjusting P1. The second stage amplifies the band of frequencies (adjustable using P2 and P3) that are attenuated by the guitar amp, so as to be able to reproduce the (lead)  singer ’s voice as clearly, distinctly, and  accurately as possible. To refine the adaptor and tailor it to your amplifier and speaker, don’t be afraid to experiment with the component values and the type  of capacitors.
The schema can readily be powered using a 9 V battery, thanks to the voltage divider R4/R5 which converts it into a symmetrical  ±4.5 V supply.

Author : Jérémie Hinterreiter

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Build a Bootstrapped Amp Current Source Wiring diagram Schematic

Build a Bootstrapped Amp Current Source Circuit Diagram. This schema responds to the difference between Vj and V2. Rq on sets gain. Resistors XR2 and (1 -X) R2 produce the bootstrap effect. These two resistors convert the schema`s output voltage to a current. IC1 and IC2 are Burr-Brown OPA2107 or equal.

Bootstrapped Amp Current Source Circuit Diagram

Build a Bootstrapped Amp Current Source Circuit Diagram

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1 Amp Current Injector Wiring diagram Schematic

This is a Simple 1 Amp Current Injector Circuit Diagram. A voltage booster provides the current control schema with a higher voltage, to insure the electronic schema operates properly, even as the battery voltage drops. A single LED provides both power monitoring and a low battery indicator. The current source is activated when a pushbutton switch is pressed. With a good digital voltmeter, you can use this device to measure resistances down to less than one micro ohm. 

 Simple 1 Amp Current Injector Circuit Diagram

That is 0.000001 ohms. I often use it to measure contact resistance of a relay or the resistance of big chunk of heavy gauge wire or the resistance of a copper trace on a schema board. You can also use it to measure the voltage drop of a power diode, when conducting one amp of current. 

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