This 555 IC circuit was found in June 1984 Radio Electronics magazine. This circuit detects a change in the signal and can power a relay or other warning system.
This oscillator was found in the November 1986 issue of Radio Electronics magazine. The frequency...
This sophisticated circuit with a low, medium, and high treble filter is from 1990 documentation. The...
This circuit was obtained from a 1998s Popular Electronics. The magazine no longer exists, but the...