DC source, Capacitor and LED

Discussion in 'General Electronics Chat' started by dipto, Dec 11, 2015.

  1. dipto

    Thread Starter New Member

    Jun 11, 2015
    4
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    I have connected a variable capacitor and a LED in series with a DC 9V source. When I vary the capacitor , the brightness of the LED changes. But how it happens?
     
    RRITESH KAKKAR likes this.
  2. dl324

    Distinguished Member

    Mar 30, 2015
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    The capacitor will conduct until it's charged. Post a schematic for a better answer.
     
  3. MikeML

    AAC Fanatic!

    Oct 2, 2009
    5,450
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    Means that the variable capacitor is shorted. Test it with an Ohmmeter.
     
  4. wayneh

    Expert

    Sep 9, 2010
    12,090
    3,027
    Your 9V source may be pulsing, and the capacitor can pass current will charging. But you'd need a large capacitor for this. Mike's answer seems more likely.
     
  5. dipto

    Thread Starter New Member

    Jun 11, 2015
    4
    1
    no, its just a 9V battery
     
  6. RRITESH KAKKAR

    Senior Member

    Jun 29, 2010
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    Which capacitor was that GANG?
     
  7. Techno Tronix

    Member

    Jan 10, 2015
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    I think there is 9-volt battery and connect to a 470Ω resistor which is in series with a 100K potentiometer connected to an LED. We use a protection diode in this circuit so that if the 9-volt battery is inserted the wrong way, the LED can be protected from reverse current.
     
  8. wayneh

    Expert

    Sep 9, 2010
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    So it's really a variable resistor, not a capacitor?
     
  9. dl324

    Distinguished Member

    Mar 30, 2015
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    Make it easier for us to help you. Post a schematic of your circuit and a picture of your variable capacitor. How do you expect to limit LED current?
     
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