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BJT IB vs VBE Characteristic

Discussion in 'General Electronics Chat' started by quinceyw@comcast.net, Jul 20, 2012.

  1. quinceyw@comcast.net

    Thread Starter New Member

    Jul 3, 2012
    I am measuring BJT DC h parameters hie and hre, so I measured the common emitter input characteristic, Ib vs Vbe for various Vce.

    For a given Vbe, Ib should drop with and increase in Vce due to the early effect, but I measure an increase in Ib with increasing Vbe. Does anyone know what mechanism might cause this? Might I have the wrong measurement setup?
  2. bertus


    Apr 5, 2008
  3. WBahn


    Mar 31, 2012
    You are saying different things at different points: You say it should drop with increasing "Vce" but that you observe that it increases with increasing "Vbe". Which of those, if either, is a typo?

    I don't recall the Early Effect saying anything regarding the base current. I recall it addressing the increase in collector current as the collector-emitter voltage increases and, thus, the collector current increasing for the same base current.