This interesting circuit, from a digital documentation two years 1978 shows how to implement a circuit that measures the position or angle of a stepper motor controlled by a microcontroller.
This balance indicator for stereo amplifiers was found in an 80's Elektor. The components used are...
This circuit can be applied to other 3-terminal regulators and equivalent transistors can be used....
As we have explored on this site many times, a 2N3055 without the cover works like a low yield...