This circuit was found in documentation two years 80. Transistors can be modern equivalents. Or circuit can be modified to operate with lower voltage.
This circuit for the VHF band of analog TV was found in Motorola documentation from the 70s. The...
This 1989 circuit activates a protection relay if one or two phases are missing from a three-phase...
This circuit for telecommunications was found in a 1987 documentation. Connected to the...