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 circuit allows the detection of RF signals using the lowest range of direct currents of a...
The MC496 integrated circuit used in this application is not common today. Motorola's circuit...
This window comparator circuit was found in a Popular Electronics from the 90s. The circuit has a...