Originally designed for WWV (Standard Time Station) signals, it lets 1 kHz tones pass by rejecting the 440 and 600 Hz tones emitted by the station. The circuit is from a 1964 Electronic Design.
This oscillator circuit for sinusoidal audio signals with operational 741 requires a symmetrical power...
Found in a 1974 Radio Shack documentation. This circuit must have a connection to the ground of...
This sensitive circuit detects the live pole of a power grid or outlet. The circuit makes use of a high...