A resistor is characterized by an always constant resistive value. With the same applied voltage, it will always pass the same amount of current. The potentiometer, on the other hand, is an electronic ...

Simply adding a diode and potentiometer to a 555 timer operating in the asynchronous mode yields a pulsewidth modulator (PWM) with a duty factor adjustable from 1% to 99% (Fig. 1). Applications would ...