This 80's circuit uses an audio amplifier to obtain a symmetrical source from a single source. The maximum current is on the order of 1.3 A and the input voltage must not exceed 20 V.
This circuit uses a contactor having been found in a 1987 publication. More modern equivalent...
This circuit was found in a 1977 Radio Shack documentation. Its purpose is to generate 1 Hz...
This circuit was found in a 1980s documentation. It decodes by identifying a certain frequency tone...