BJT

Thursday, 11 July 2019

2:15 PM

    Current controlled devices

    Machine generated alternative text:

     

    Machine generated alternative text: The collector current, lc, of a transistor is the amplified output current of a bipolar junction transistor. There are several ways to find the collector current, lc, of a transistor. And it all depends on what information is already known about the transistor: 1st Way to Calculate Collector Current lc Using Known Values If the base current, 1b, and are known, then lc can be computed by the following formula: lc=ßlb Example If lb=36pa and $100, then lc calculates out to be: Ic=ßlb = 3.5ma 2nd Way to Calculate Collector Current lc Using Known Values If the emitter current, la, and are known, then lc can be computed by the following formula: IE Example If le=4ma and $160, then the value of lc is computed to be: 150 IE— — (4ma)= 3.97ma 151 3rd Way to Calculate Collector Current lc Using Known Values If base current, 1b, and emitter current, la, are known, then lc can be calculated by the formula: lc=1E-1b Example If le=4ma and lb=30pa, then lc calculates out to be: Ic= IE -1b = 4ma - 30ga= 3.97ma

     

     

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    • Disable voltage and current sources
    • Mid, High -> Short external capacitor
    • Replace BJT and MOSFET with small signal
    • Low, Mid -> Open internal capacitor
    • High -> Keep internal capacitor

     

 

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