Wrong. The LED itself is an interrupter. It fires an arc from a prong to a dish repeatedly and constantly at a rate of several million arcs per second. The actual amount varies by colour. All resistors do for LEDs is prevent you from wasting energy by over-feeding the LED. They do not change the workings of the LED.
Sorry; I know I'm fairly new here but I have to disagree - at least in part...
From what I have learned in my years of working with and schooling in electronics; with an LED there is a wire (whisker) from the prong to the anvil; but there is no arcing involved. Light is emitted by the free electrons in the PN junction area loosing energy and falling back into a stable orbit around its nucleus. The colors are primarily determined by what doping material is added to the PN junction of the chip that is positioned in the dish. The anvil holds the dish (reflector) and the prong and whisker only provide the 'positive' charge to the PN junction. As long as a forward biased voltage is applied there will be conduction across the PN junction and light will emit as long as that voltage is there.
On second thought; I guess I can see where it could be said that it was 'arcing' because of the fact that each electron loosing energy emits a photon of light. millions of these happening every second make it appear constant. Maybe I should just disagree with the term arcing?
As for the resistor; yes, that is basically to provide a constant current source to the LED and keep from over feeding it. A good example is to hook up an LED directly to a battery. It works (assuming polarity is correct) but the LED will get very hot very fast. Add in the appropriate resistor for the LED and there is no real change in brightness; however the LED will not get as hot as fast.
AC