Found in Exar documentation from the 1980s, this circuit has a 60 dB cutoff at 1800 Hz. The circuit can be adapted to operate at other frequencies.
This low drift or offset circuit is from an 80's documentation. The configuration can be made with...
We found this circuit in a 1956 Sylvania publication. It serves to monitor telegraph transmissions being...
This circuit activates an incandescent lamp at dusk and goes out at dawn. The sensor is an LDR and...