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.
We found this circuit in an old documentation, using an operational of the time. The circuit...
This circuit shows how to use a 3-terminal voltage regulator as a low frequency oscillator by...
The circuit bellow uses two NPN transistor to drive heavy loads up to some amperes. The maximum...