Found in a Raytheon transistor manual from the 1950s, this circuit uses one of the first commercially available transistors, the CK722. The circuit is for using a small speaker as a microphone.
This amplifier for effects on musical instruments can be mounted with BC549 transistors. The...
We found this circuit in documentation from National Semiconductor. For the medium wave range the...
According to what is said, the bugs are the female insects (mosquitoes, muriçocas and others)....