This circuit was suggested by General Electric / RCA in a 1980s documentation. The components are of the time and the circuit must be powered by symmetrical source.
Suggested by General Electric documentation from 1968, this circuit activates a relay after 60...
This high-Q low-pass filter was found in the October 1990 issue of Radio Electronics magazine. The...
Found in Motorola's 1967 documentation this circuit can use any general-purpose transistor. The signal...