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Plasma inside a light bulb?

  1. Oct 19, 2013 #1

    is something like this even possible in a light bulb? i thought the interior was supposed to be a vacuum.
  2. jcsd
  3. Oct 19, 2013 #2

    D H

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    The thin glass used in a typical incandescent light bulb is not near strong enough to sustain a vacuum. Incandescent bulbs are filled with inert gases to about 70% atmospheric pressure.
  4. Oct 19, 2013 #3


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  5. Oct 21, 2013 #4


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    The lights at the back of a car include a combined rear light / brake light bulb.

    Usually this is replaced when one of the lamp filaments burns out.

    This gives you a chance to experiment since you now have a working filament and a disconnected wire which will work as an anode if the filament is supplied with its normal voltage. It will work as a diode if the bulb is under vacuum or as a plasma display if it contains gas.

    Local repair shops usually discard such bulbs but would probably save you a few if you ask.
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