This circuit is designed to control static loads fed by direct voltage. The circuit is from Motorola documentation from 1968. Equivalent SCRs may be used depending on the load.
This is an old test circuit for integrated TTL counters, feeding a Nixie tube, common at the time....
This traditional crystal radio circuit, but which has a modern version with diode, was found in an...
This headphone amplifier using a pickup coil can be used as an extension for devices such as TVs,...