Our eyes are very sensitive to light but they cannot see the IR (Infrared) radiations so it is some time difficult to test or check the equipments which emits infrared to confirm that either they are working or not. So here is the IR detector circuit which will detect IR from any equipment which
emits IR and lights up an LED which will show the indication of IR beam. The heart of the circuit is Phototransistor T1 which will detect the infrared beam. The transistor T2 is working as an amplifier which amplifies the output of T1 and lights the LED which indicates that your equipment is working and emitting infrared beam.