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.
This circuit was found in the March 1982 Radio Electronics magazine. The component is a special...
This 1969 Electronics World power supply has 5 V to power digital circuits and a 170 V output for...
Found in Radio Electronics from the 90s, this circuit uses a thermistor as a sensor that can have...