The purpose of this circuit is to emit infrared pulses. However, LEDs for visible light can also be used. Power must be 5 V and the transistor may be general purpose types. The circuit can be used to operate as a shield.
This circuit has an LED indication of the timing progress, having been found in an old...
This circuit is from a Radio Electronics magazine from August 1974. It used one of the first...
This charger is powered by the car's 12 V socket, the number of diodes being calculated according to...