This circuit was found in a Popular Electronics of the 1980s. The microammeter may be the lowest current range of a multimeter. The antenna is telescopic.
This two-transistor amplifier can be used as power stage for intercom, experimental receivers,...
This proximity relay circuit was found in the July 1990 Radio Electronics magazine. The supply...
With an ultra-low consumption, this circuit can be powered by solar cells. The circuit is from a...