Suggested by General Electric in a 1968 documentation this integrated amplifier uses a component of the era, the PA237. The circuit runs on 24 V and excites a 16-ohm speaker.
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...