We found this circuit in a 1986 documentation. It uses only LEDs, batteries, resistors and the power supply which can consist of 4 batteries or a 9V battery. The basic circuit uses two-color LEDs.
This circuit works with small 5 V incandescent lamps but can be modified to operate with LEDs. The...
This circuit found in Radio Electronics can be used in games to produce a random pulse train. The...
This photometer is based on a Wheatstone bridge that must be balanced by the linear potentiometer P1. The...