Found in an 80's Elektor, this circuit can use any equivalent optical coupler. The buzzer is of the Sonalert type with included oscillator.
We found this circuit in a Harris Semiconductor Databook of 1977. The circuit can be implemented with any...
The inverter circuit shown in the figure can be used to power a fluorescent lamp in an emergency...
This circuit was found in an American documentation two years 80. The MOSFET is of double port,...