This circuit was found in Motorola's 1968 documentation. It can be built on current equivalent components. The bridge diodes and the SCR must be in accordance with the current of the controlled motor.
For reference only, this is the first IF amplifier stage of a common transistor radio from the...
This circuit from July 1975 Radio Electronics uses any operating system with a symmetrical source....
This setting is valid for other transconductance operational amplifiers. The circuit is from...