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 is one of the many versions of this type of indicator that the reader can find on our...
This circuit is from a manual of linear integrated circuits of the 80s. The operational is of the...
This circuit has a 100 dB dynamic We found it in a Popular Electronics from the 90s. Equivalent...