This document discusses the design of an infrared transmitter and receiver circuit to understand their working. It describes the key components used, including an IR LED transmitter that emits infrared photons, an IR photodiode receiver that enters a breakdown region when infrared photons are detected, and a circuit connecting the two with batteries and resistors. The circuit aims to demonstrate the working principles of how infrared signals are transmitted and received, with potential applications in automatic lighting, counting, security, and theft alarms.

1. Aim
To understand the working of infrared transmitter and reciever and to design
the circuit to understand their working.

2. Introduction
Infrared transmitter is a LED which transmit the photons in wavelength range of
infrared waves.
Infrared transmitter is a photodiode which is used in reverse biasing and it
enters into break-down region when any infrared photon is incident on it.

3. Apparatus used
IR transmitter
IR reciever
Circuit board
Wires
9V batteries and battery connectors
LED (5mm, 1.5V)
Resistors

4. Theory and working
Working of IR transmitter or IR LED

6. Working of IR reciever or IR photodiode

7. Circuit used in designing of IR transmitter and IR reciever

8. Sources of errors
Write yourself
Precautions
Do not connect any electronic component without resistance in series, it can
burn the component.
Applications
In automatic switching on-off of lights, counters, security systems, theft alarms.
Bibliography
NCERT textbook of class 12
Physics by S.L.Arora
Circuits available on internet