Comment on Why do surge protectors continue to draw power from the wall even if switched off or if nothing's connected to them?

mvirts@lemmy.world ⁨1⁩ ⁨year⁩ ago

• FuglyDuck@lemmy.world ⁨1⁩ ⁨year⁩ ago

  Surge protectors don’t use capacitors.

  They use a variable resistance circuit- usually metal oxide varistors. When the supply is at the correct voltage, it just goes through them. When it’s too high (a surge,) the resistance increases and excess voltage is sent out a fork to ground

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  • mvirts@lemmy.world ⁨1⁩ ⁨year⁩ ago

    Oh! Yeah that makes sense… idk why I thought they mainly used a capacitive circuit. So those varistors must dissipate power in normal operation right?

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    • FuglyDuck@lemmy.world ⁨1⁩ ⁨year⁩ ago

      Varistors change their resistance loads depending on the voltage coming into it. the hot wire is connected to ground, and when in normal voltages, they’re very high resistance. electricty follows the path of least resistance- similar to water flowing down hill.

      so, when the voltage is normal, the power goes into the plugs does it’s thing. when a surge hits, the MOV’s loose resistance with the increased voltage, letting it flow into the ground wire instead. This brings the voltage going down the hot wire to normal, until the MOV’s go back to being highly resistive, and normal power.

      basically, think of it as being a water wheel, when the flow of water is ‘normal’, the sluice gates are open and the water goes down the sluice driving the wheel. when there’s a lot of water coing in, though it spills out and doesn’t make the wheel spin too fast.

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• mvirts@lemmy.world ⁨1⁩ ⁨year⁩ ago

  Side note, if you ever want to get real mad about paying money for something open up a cheap surge protector or power conditioner 😹

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  • Alchemy@lemmy.world ⁨1⁩ ⁨year⁩ ago

    Just empty shell with low grade solder and cheap wiring?

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    • FuglyDuck@lemmy.world ⁨1⁩ ⁨year⁩ ago

      That would be a “power strip”- but the surge protectors do have rather little in them all the same. The varistors are where the magic is- and they’re basically about the size of a grape. Or a coin.

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