The configuration shown was found in the October 1974 Radio Electronics magazine. The integrated circuit used is the CD4001 and the power supply depends on the application.
In the figure we have an improved method of varying the voltage of a 7812 regulator. The circuit is...
This 5-range current measurement circuit was found in the September 1989 issue of Radio...
Found in an old English publication this circuit uses a dual gate MOSFET. Coils not specified....