Common emitter amplifier question

Discussion in 'General Electronics Chat' started by jmsparkland1, Apr 1, 2012.

  1. jmsparkland1

    Thread Starter New Member

    Feb 29, 2012
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    I don't understand how current can flow through the base as shown in img2 can happen if the transistor has an inner diode as shown in img1. Any help?
     
  2. Audioguru

    New Member

    Dec 20, 2007
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    The base-emitter of a transistor is a silicon diode. For the NPN transistor you have its anode is the base and the cathode is the emitter as you showed in img1. It needs about 0.6V to conduct.
    The positive voltage from the solar panel (more than one 0.5V solar cell) connected to the base as you show will cause base current to flow and cause the transistor to turn on.
     
  3. jmsparkland1

    Thread Starter New Member

    Feb 29, 2012
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    .6v causes the current to flow which way?
     
  4. MrChips

    Moderator

    Oct 2, 2009
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    AAC uses electron flow to indicate current. Hence the arrows indicate the direction of electron flow.
     
  5. Audioguru

    New Member

    Dec 20, 2007
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    Instead of worrying about "conventional current flow" or the reverse which is "electron current flow", simply learn that when a diode is forward biased then it conducts current. When a diode is reverse biased then it blocks current flow.
    A diode is forward biased when its anode is positive and/or its cathode is negative.
     
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