This circuit was found in the October 1987 Radio Electronics magazine. The circuit is a PWM control with a 555. It appears that the 555 is missing a connection that would be pin 4.
This circuit emits an audible signal when the mains voltage ceases. The circuit is from a 1973...
We found this circuit in a 1966 RCA manual. The integrated circuit is unusual, and the Triac must...
Short duration pulses or "clicks" can be generated with the circuit seen in the figure. The...