Found in an Elektor from the 90's, this double door-bell drive circuit switches a relay by triggering different points.
This filters blocks radio interference or noise coming from the AC Power line. Noise such as the...
This circuit was suggested by Motorola in its manual of components for optoelectronics (1987)...
The output current of this circuit reaches 12 mA. The zener diode determines the output voltage. The...