This circuit was found in documentation for radio amateurs of the 1980s. This is the so-called roger-beep, which is the beep that is transmitted when the talk-listen function is changed.
The sensors in this circuit, found in a 1999 documentation, are stripped wire tips at different levels...
This traditional crystal oscillator configuration can use any CMOS gate configured as an inverter. R1...
This amplification stage circuit with a germanium transistor was found in a 1980s documentation. The...