This circuit was found in a 1967 US publication. In it we have the implementation of a ring counter using only relays. Relay free contacts can trigger indicator lamps or LEDs.
In the figure we have a practical idea for using the good junction of a partially burned...
This amplifier is from Motorola documentation from the 70s. The circuit uses transistors from the...
This positive voltage regulator with 70 V output was found in a National Semiconductor manual from...