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.
We found this circuit in a 1978 documentation. The SCR conducts when the regulator's output...
This small audio amplifier can be used with microphones and other audio sources. The circuit can...
This source for 50 W amplifiers per channel was found in 1967 Delco documentation. Transistors are from...