Found in a Popular Electronics from the 90's, this circuit detects the approach of objects by the reflection of the radiation emitted by the LED. The relay is a 12 V sensitive type.
The existence of field effect transistors at the input of the integrated circuit (operational...
This circuit has a maximum output current of 5 A, and the 2N3055 must have an excellent heat sink....
This circuit is suggested by Motorola and is based on a 1723 voltage regulator. The 2N3055...