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.
March 2017 - Mouser Electronics announces its new TPSA89 voltage regulator from Texas Instruments with...
This Harris circuit from the 90's is intended for recording old EPROM memories. The circuit uses...
We found this circuit in an old Radio Electronics. The transistors can be the BC548. The circuit...