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 powerful amplifier with output in complementary symmetry is from an old documentation....
This transistorized oscillator, a modification of the Colpitts oscillator, was found in the...
Found in Popular Electronics from the 90s, this generator uses integrated circuits from that time....