Transistor without base pin.

Discussion in 'General Electronics Chat' started by cjdelphi, May 27, 2009.

  1. cjdelphi

    Thread Starter New Member

    Mar 26, 2009
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  2. beenthere

    Retired Moderator

    Apr 20, 2004
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    In the case of an NPN transistor, the base needs to be about .7 volts more positive than the emitter.
     
  3. Audioguru

    Expert

    Dec 20, 2007
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    Look at the datasheet of any silicon transistor. The absolute max allowed emitter-base voltage (reverse voltage) is only 5V to 7V. Because any higher and the junction conducts with "avalanche breakdown".

    This oscillator circuit has the emitter-base junction conducting with avalanche breakdown and it is in series with the forward-biased base-collector junction. That is why it uses a 12V supply.
     
  4. radiohead

    Distinguished Member

    May 28, 2009
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  5. mik3

    Senior Member

    Feb 4, 2008
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