What is bulb

Discussion in 'General Electronics Chat' started by Vindhyachal Takniki, Mar 6, 2016.

  1. Vindhyachal Takniki

    Thread Starter Member

    Nov 3, 2014
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    1. In attached pic what is this bulb. In circuit it is directly connected to 220Vac manis via a 470k resistor as you can see pic.
    It has two filaments is it as you can see. What ac is applied it both glows. But when ac is given by clipping negative half by a diode, only one filament glows.
     
  2. Jony130

    AAC Fanatic!

    Feb 17, 2009
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  3. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Neon if fed from AC both electrodes glow, if DC then only one glows.
    Max.
     
  4. Vindhyachal Takniki

    Thread Starter Member

    Nov 3, 2014
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  5. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    Its a neon bulb, they have a strike voltage of approx 70V, they make ideal mains indicators with a series resistor.
     
  6. MaxHeadRoom

    Expert

    Jul 18, 2013
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    A Neon is also used in the tester type mains screwdrivers that use body conductance to earth to indicate a live circuit, the pocket clip has to be held in order to complete the circuit for the neon to light.


    [​IMG]
    Max.,
     
    Last edited: Mar 6, 2016
    Vindhyachal Takniki likes this.
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