This 1967 Raytheon circuit uses a Raystor, an optical coupler with a lamp and an LDR. The circuit can be adapted to use another type of coupler.
This circuit uses components that are still common despite being from 1995 documentation. The circuit can...
This filter was found in Delco's 1965 documentation. It can be implemented with modern components...
This circuit was found in an old publication and can be adapted for use with modern...