This circuit provides a reference voltage of 2.5 V adjusted in the trimpot. The transistor can be the BC558 (in the drawing it came out as NPN). The control is done by a rectangular input signal.
Lamps in the range between 20 and 50 mA can be used. Voltage supply is according the lamp and...
The purpose of this circuit found in an old documentation from the 90's is to switch on low...
This configuration, which appears elsewhere on this site, was found in documentation from the...