I've heard that one of the applications of PWM is to control the intensity of a light source (e.g. as in a dimmer). My question is, if you send a square wave voltage with a certain duty cycle to a lamp, it seems to me that it would have to be at a high enough frequency that humans wouldn't perceive the flicker. Ok, so if the frequency is that high, then answer me this: When the square wave is high, the lamp has the full voltage across it and lights up at maximum intensity. When it's low, the lamp is off. These are the two states of the lamp. If the periods of maximum intensity blur together, then why doesn't the lamp simply appear as though it is on at full intensity, continously (regardless of duty cycle)? Why on earth would the bulb behave as though it were being exposed to a lower voltage that is the *average* of the waveform?