This circuit was obtained from an old Signalite documentation. Neon lamps are special types of the time. The operation occurs at low frequencies.
This 1967 Raytheon circuit uses a Raystor, an optical coupler with a lamp and an LDR. The circuit...
The basic idea of this circuit is to indicate the tolerance of a capacitor by reference to a...
This circuit is from an English publication from 1973, but can be easily assembled today. 2N718 can...