We found this circuit in documentation from the 90s. It is a common configuration that is given in two versions, using transistors and using two integrated inverters.
This battery-powered micropower supply was shown in Radio Electronics magazine in 1991. The...
Found in a 1965 Electronic Design, this circuit can be made with modern equivalent transistors. The...
In this circuit, the current in solenoid X1 can be adjusted and its intensity measured to the...