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 sensitive Japanese mid-wave receiver from the 1960s has an output power of 45 mW and is...
This circuit appeared in a Radio Electronics magazine in March 1962. The circuit uses two...
What's different about this transistorized circuit is the fact that it doesn't use a voltage...