This circuit makes use of a low impedance microphone. The relay is according to the supply voltage which can be between 9 and 15 V. The operational gain is approximately 100.
This circuit makes it possible to recover programs recorded on cassette tape as was common in MSX...
This ultra-simple adjustable power source is of great use on the bench of any electronics...
Found in a 1990s American technical brochure, this circuit is intended for alarms that use as...