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.
Using a zener diode it is possible to change the linearity of the scale of an analog instrument by...
This circuit causes the relay to be energized when the input voltage exceeds the voltage value of...
This circuit can be used in 0,5 to 37 V Power supplies and output currents up to 3 A. The...