This is the receiver for the previous circuit we found in the December 1992 Radio Electronics magazine. The sensor is a photodiode that must have optical features such as lenses.
A low voltage heating element (up to 30 V) with a current of up to 3 A can be precisely controlled with...
This protection circuit for battery chargers was found in an old Elektor. The relay is according to...
This is a circuit for testing small lamps and LEDs. The lamps that can be tested are the ones...