Found in a 90s Popular Electronics, it serves both TTL and CMOS logic. The injector can provide 10 kHz or 100 Hz signals. The circuit drives a transducer and two LEDs.
This circuit was obtained from an English magazine from 1979, but can be easily assembled...
The purpose of this circuit is used in communications and to respond to signals that are in the 2...
This circuit was found in the November 1989 Radio Electronics magazine. Power supply depends on...