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 circuit was found in documentation from the 70s. We can try current JFET transistors....
This is the power supply circuit for the amplifier in the previous circuit. The source is...
This bridge circuit is designed for 8-ohm speakers delivering a few watts of power. The circuit is from...