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: