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 September 1996 issue of Electronics Now magazine. The sound provided has...
We found this circuit in a March 1961 Radio Electronics magazine. This circuit reaches 100 MHz...
Using the M1575 this switching converter was found in National Semiconductor documentation from...