This circuit is from a Radio Electronics from August 1992. The transistor used allows the control of motors up to about 5 A. It must be equipped with a heat sink.
This circuit matches a source of high or medium impedance audio signals with a low impedance...
Found in a 1993 Electronics Hobbyst Handbook, this circuit uses components that are still common...
This pulse width-tuned circuit was found in the March 1996 issue of Electronics Now magazine. The...