This notch filter was found in National Semiconductor documentation from the 1980s. Operational amplifiers are from that era. The configuration can be adapted to use modern operational amplifiers.
This circuit triggers an alarm in the event of a power failure. The circuit is from an 80's...
We found this circuit in the April 1978 issue of Radio Electronics magazine. The 2-digit circuit uses...
This CMNOS crystal-based circuit generates a 2 Hz signal. It was found in the October 1994 issue of...