This Wien bridge oscillator circuit uses a Texas Instruments 709 amplifier. It was found in an article in the September 1972 issue of Radio Electronics magazine. It is powered by a 24 V voltage.
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....