This 1977 circuit only allows the solenoid to energize if the right combination of switch positions is selected. The relay is 6 or 12 V depending on the low voltage supply used.
This sensor circuit from a 1967 Ferranti documentation uses components from the era. The circuit...
This circuit was found in the November 1992 issue of Radio Electronics magazine. The circuit has...
This circuit eliminates hiss and other noise from audio sources by cutting frequencies above 10...