In this charger the current is limited by the incandescent lamp. Lamps from 40 to 100 W can be used and even connected in parallel, depending on the load.
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...