Found in a 90's EDN this circuit can be used as a shield. The transistor is a general-purpose type and the frequency of the emitted sound is determined by R1 / C1.
Suggested by a 90s Radio Elecrtronics, this circuit is intended to supply mobile equipment of the time....
The illustrated circuit uses the AUIRS2301 S from International Recfifier (www.irf.com) and is...
This circuit uses an FM IF transformer for tuning. The circuit is from a Radio Electronics...