This circuit was found in the June 1991 issue of Radio Electronics magazine. The circuit uses two Hall effect sensors of the time. It can be assembled using modern equivalents.
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...