This speaker overload protection circuit was found in Radio Electronics from the 1980s. The circuit uses a 9 V relay but can be powered by 12 V for a relay of this voltage.
This filter with the 741 op amp was found in the February 1995 Electronics Now magazine. The power...
Found in an American documentation from the 90s, this circuit makes use of an output transformer for...
This directed coupled amplifier uses a transformer to drive a low impedance loudspeaker. This...