We found this circuit in a 1973 publication. The circuit lets frequencies below 480 kHz pass through with an output impedance of 1k. The circuit can be implemented with current operational.
Found in a 90s nHands On Electronics, this circuit triggers a relay that shuts off the load when...
Another of the many similar configurations we have in this section. This one is from a Radio...
This circuit for incandescent lamps was found in the January 1980 Radio Elecronics magazine. The...