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.
Found in a 1967 Delco documentation, this circuit can deliver power from 40 to 50 W at 8-ohm load....
This Intersil circuit was found in a 1980s documentation. Operational are of the time, but current...
We found this circuit in a 1980s American publication from Motorola. Modern equivalent transistors...