User:DavidB4/workspace
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A dimmer switch is a device which allows for the adjustment of power supplied to one or more electric lights. In some rare cases, they are also used for other electric devices, but in many cases doing so would harm the device, so this is rare.
Types
Rheostat (variable resistor)
The first kind of dimmer switch made use of a variable resistor. In this kind of device, a semiconductor strip is placed between two contact arms--one is stationary, one is adjustable. The semiconductor permits the flow of electricity, but does resit it somewhat. The stationary contact arm is placed at one end of the semiconductive strip, and the adjustable one is permitted to move across it. When the latter arm is placed right near the stationary arm, electricity flows from one arm through a small amount of the semiconductor, and out to the other arm. Since it only passes through a small amount of semiconductor, the power flow is minimally effected. However, when the adjustable arm is moved down the strip, away from the stationary arm, the amount of semiconductor the power must flow through increases. This prevents progressively more electricity from passing through, as the arms separate.[1]
This simple system is then installed in a switch, where the user can easily move the adjustable arm. The resulting supply is then connected to some device, usually a light bulb. If the operator wished for a higher power supply, they can simply slide or twist the dimmer control to decrease the amount of semiconductor the energy must pass through. If the operator wishes to reduce the electrical supply, the amount of used semiconductor can be increased, by sliding or twisting the control in the opposite direction.[1]
Unfortunately, while this setup does allow for easy adjustment of the electrical supply, it is inefficient. Much of the energy which would have gone through the controller is instead converted to heat. This causes the output voltage drop desired, but most of the electricity is still being used, as it is converted into heat energy. In some cases, this can also be a safety hazard since the heat can build up and potentially cause fire or other damage.[1]
Switching circuit
Triode alternating current switch
Coil-rotation transformer
Autotransformer dimmer
(Variac)
Solid-state
(aka semiconductor)