Found in an old Elektor, this circuit uses two 7-segment displays to indicate the volume of an amplifier. The circuit uses components that are still common today.
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...