This 12.5 W quasi-complementary amplifier was found in a 1969 General Electric publication. Note the high supply voltage. Transistors are common types at the time.
This circuit uses a Hall device from that time as a sensor. The circuit is from an English...
Found in Radio Electronics from the 90s, this siren finds many variations on this site. The...
This audio generator that produces both rectangular and sinusoidal signals was found in a...