We found this circuit in the July 1969 Radio Electronics magazine. The circuit uses a coupler made with a lamp and an LDR. The power of the lamp determines the types of diodes.
The configurations of the two previous circuits can be modified to operate with a simple power...
) This circuit was found in a 80’s Popular Electronics. It issues a warning signal with the signal...
This circuit also makes use of a field effect transistor (JFET) which can be the BF245 and has an...