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    Default How do dimmers work? Electricians?

    Hey, so for a household light, running an incandescent bulb that uses say 100w, if you dim it using a "normal dimmer switch", are you saving electricity? Or does the dimmer just use up some wattage and turn it into waste heat?

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    Modern dimmer switches definitely reduce energy consumption. Not 100% sure if you have really old ones - my understanding was the older dimmer switches did burn off the extra power right at the switch. They still might reduce power usage but it's not as linear.

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    Not really answering the question, just love the accent.

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    Quote Originally Posted by ExtraSlow View Post
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    Hey, so for a household light, running an incandescent bulb that uses say 100w, if you dim it using a "normal dimmer switch", are you saving electricity? Or does the dimmer just use up some wattage and turn it into waste heat?
    I honestly don't know the science of it, but if the dimmer switch was just producing waste heat our switches would be burning hot.

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    Quote Originally Posted by ExtraSlow View Post
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    Hey, so for a household light, running an incandescent bulb that uses say 100w, if you dim it using a "normal dimmer switch", are you saving electricity? Or does the dimmer just use up some wattage and turn it into waste heat?
    No google?

    Modern dimmers are built from semiconductors instead of variable resistors, because they have higher efficiency. A variable resistor would dissipate power as heat and acts as a voltage divider.

    Since semiconductor or solid-state dimmers switch quickly between a low resistance "on" state and a high resistance "off" state, they dissipate very little power compared with the controlled load.
    https://en.wikipedia.org/wiki/Dimmer
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    The layman's analogy of a dimmer was explained to me using plumbing: is not the same as turning down a faucet to a trickle, but rather opening and closing the faucet very fast.

    Yes, you are definitely saving some power usage.
    Last edited by revelations; 02-07-2020 at 07:57 PM.

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    Quote Originally Posted by revelations View Post
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    The layman's analogy of a dimmer was explained to me using plumbing: is not the same as turning down a faucet to a trickle, but rather opening and closing the faucet very last.

    Yes, you are definitely saving some power usage.
    Is this why led bulbs don't work well with them?

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    That's more to do with the ballast that powers the LED IIRC. All my LEDs are dimmable, no discernible difference from the other dimmers/regular bulbs elsewhere in my house.

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    Quote Originally Posted by ExtraSlow View Post
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    Hey, so for a household light, running an incandescent bulb that uses say 100w, if you dim it using a "normal dimmer switch", are you saving electricity? Or does the dimmer just use up some wattage and turn it into waste heat?
    For a regular 100 watt incandescent bulb on an old school variable potentiometer, there would be little to no energy savings as the potentiometer will dissipate any increased work it's doing as heat. Now it won't be anything significant in heat if it's a properly sized potentiometer.

    Most dimmers are not old school and work differently so yes, there would be energy savings but those energy savings could come at the cost of shortened bulb life in the case of some bulbs.

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    Quote Originally Posted by ipeefreely View Post
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    No google?
    If I wanted to know, I'd check google. If I wanted to talk about it, and hear peoples opinions, I'd post on beyond.ca

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    I had thought they were rheostats.

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    Quote Originally Posted by ThePenIsMightier View Post
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    I had thought they were rheostats.
    Potentiometers and rheostats are both variable resistors.

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    I went through a year where I thought the Rheostatics were THE COOLEST BAND.

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