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.
Found in documentation from the 1980s, this circuit can be used with other operational ones. The...
This circuit was published in the December 1987 Radio Electronics magazine. It uses two 555s to...
This circuit identifies the polarity of DC signals and if the signal is AC. The circuit is from...