This circuit allows the use of an electret microphone with a 1.5 V source. We found it in the Encyclopedia of Electronic Circuits volume 5 from 1995.
The purpose of this receiver is to monitor the signal from a nearby transmitter. It was published in an...
This suggested application of the integrated 78xx voltage regulators is from one of the many...
Presented as an electronic siren, this circuit was found in Radio Electronics magazine from June...