Lar & Others FYI: The heart of those inexpensive little dimmer units is a solid state device known as an SCR or Silicone Controlled Rectifier and they work like this. When you adjust the knob on the dimmer, you are setting the point on a sine wave at which the SCR will begin to conduct. Once the device begins to conduct it will continue to conduct until the applied voltage passes through zero. The nature of AC current is that it will pass through zero twice in every cycle, once when it begins the positive swing of the cycle and again as it passes into the negative portion of the cycle. The rapid rise in current at the point of cut-in is very rich in RF harmonics and that is the reason you can hear the 60 hz hum from these units in any AM radio that is not tuned to a station. Actually what you are hearing is a 120 hz hum rather than 60 hz, because you hear the transition on both the positive and negative portion of the sine wave. Some of the more expensive devices have filters built in that reduce or eliminate this RF component of the dimmers operation. That is why I specified that cheaper is better. Just keep in mind that the radio must be on AM and if you are in a building that is wired in conduit you may not be able to pick up the signal but if a junction box is left without a metal cover the signal will be heard at the box. Dale