Found in American documentation from the 90s, this circuit uses a high voltage relay and has no grid isolation. The high values of R1 and R2 prevent the shock when it touches the sensors.
You can measure capacitances across a large range of values using the AC Power line frequency as...
This circuit had its assembly described in a Radio Electronics from March 1963. The circuit uses 2...
This transmitter for the 2-meter range with a power of 1.5 W was found in a magazine 73 for radio...