"Ron you are sssssssssssoooooooooooooooo far over my head."
Miriam, not really. I'm trying to accomplish the same as you are with the dimmer switch for your Dremel. I'm using the inline foot control as a "dimmer" switch. I can set it at 6 different levels. If I set it at the lowest level it will allow the "down stream" foot control to only reach a maximum of very slow. The next level of the inline will allow a little more maximum speed of the "down stream" control. And so on up to the six level not affecting the "down stream" controller whatsoever.
The purpose is to limit the maximum speed of my sewing. I am not expert at controlling speed. This allows me to control the maximum speed and gives more graduated increments of speed. Same as your dimmer switch regulating the speed of your Dremel.