the magic of dimmers: how do dimmer switches work

[The Magic of Dimmer Switches]

[by B.K. Electric Services]

What is a light switch?

• A light switch turns a light On or Off. That’s it. No freaky filters or disco options. Just plain ol’ “on” or “off”.

What is a dimmer switch?

• A dimmer switch not only turns a light on or off, but it can dim a room for a romantic date or light it like a spotlight.

The Early Dimmer

• The first dimmer was designed and invented by inventor Granville Woods in 1892 for theater use. These were made using heavy transformers and resistors.

• These early attempts used something called a variable resistor, which was usually a rheostat.

• Rheostats controlled electrical resistance without interrupting the flow of current.

• These variable resistors had a loop of resisting material and two contact arms (one stationary, one moving).

• The brightness of the light depended on how much resistance the electricity had to travel through.

• Less resistance = brighter light

• A knob turned the contact arm, which was touching the resisting material.

The slinky is the resistance. The electricity has to travel through more resistance to get to the contact arm. This

means a dim bulb.

The contact arm is turned to the left now, which means the electricity travels less. This means a brighter bulb.

The Move to Modern Dimmers

• The problem with these old dimmers was that you were still using the same amount of energy.

• The resistor would heat up and could burn you or your house.

• Sometime in the ‘60s, Lutron produced the first electronic solid state dimmer.

• Electronic and solid-state components mean smaller, lighter dimmers that could be used in the home.

The Modern Dimmer

• Today’s dimmer switches interrupt the circuit by rapidly shutting it off.

• The modern dimmer uses alternating current (AC).

• AC moves in a sine wave, moving up, then down in a cycle.

Two cycles of a sine wave.

• AC moves at 60 cycles per second.

• Modern dimmers trim these waves by interrupting the circuit.

• One cycle is cut twice or about 120 times per second.

• If sine waves were going to a club, their purses would be the parts cut off.

Sorry ladies. The purses stay up front.

Basically…

• That is the gist of how modern dimmers work.

• The brightness of the light depends on how fast the dimmer turns the circuit back on.

• Modern dimmers don’t heat up as much as their predecessors.

• Less energy is wasted and the electricity bills are kept low.

Resources

• Want to know more? Visit these sites – howstuffworks.com

– Bkelectricservices.com/electrical-outlets-switches-and-dimmers

• Need a dimmer installed? Contact B.K. Electric Services – (310) 430-2300

– Visit us at www.bkelectricservices.com/