Found in 90s Radio Electronics, this shield can control high voltage loads in the power grid. Isolation is guaranteed by the use of an optical coupler.
This signal injector circuit, an astable multivibrator, was found in a 1971 magazine. The circuit can...
This circuit that can only be used with simple resistive and inductive loads (never electronic) was...
This circuit activates a relay at dawn. The relay can be used to sound an alarm, turn on a radio...