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 circuit is a driver for R-2R network of AD converters. We found it in manufacturer...
This circuit was found in an American publication from the 60's. The transistor is made of...
This circuit produces an audio tone on the speaker or magnetic capsule. Rx must be such that added...