With this circuit it is possible to vary the resistance by adjusting the mark/space reaction of the 555. The circuit was found in the November 1989 Radio Electronics magazine.
This Darlington circuit is intended for the production of very low frequency signals. The...
Due to its low working voltage, this circuit of an old EDN can be associated with a...
In the figure we have the application of a general purpose diode in the gain control of a...