This 4093 IC continuity tester was found in the November 1986 Radio Electronics magazine. The circuit powers a ceramic buzzer with a frequency setting.
This is the circuit of a turntable from the 1970s. We found it in a repair article in the December...
This circuit divides the grid 60 Hz frequency to obtain 20 Hz to drive mechanical watches used at...
This small audio amplifier uses an uncommon integrated circuit today. The circuit is from a...