This is one of the first radios with an integrated circuit. The circuit is from a Radio Electronics from November 1969. The circuit is powered by a 9 V battery.
This configuration uses the 4 gates of a 7401 integrated circuit. The capacitors determine the...
This is a precision half-wave rectifier, suggested by Texas Instruments. Diodes are commonly used,...
This circuit is suggested by National Semiconductor in its 1994 Linear Applications Handbook. The...