This circuit was found in a 90s Popular Electronics. The integrated circuit used is uncommon today. The power is about of 2 W.
The circuit, shown in the figure, consists of an audio oscillator that generates signals between...
This circuit was found in a 1992 PE Hobbyst. The circuit detects the presence of spy...
This circuit produces low power flashes in a LED. Frequency is adjusted by P1 and depends also on...