We found this simple protection with zener diode in a 1967 Motorola documentation. The zener diode is 18 V, but the components can be changed for operation with other voltages.
This circuit doubles the pulse rate produced by a digital TTL circuit. The circuit is from a 1976...
This alarm with automatic shutoff was found in the April 1975 Radio Electronics magazine. The...
This 12 V to 110 V inverter with 100 W was found in a 1977 Signetics manual. The transformer must...