The Hybrid Equivalent Model The following hybrid parameters are developed and

The hybrid equivalent model the following hybrid

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The Hybrid Equivalent Model The following hybrid parameters are developed and used for modeling the transistor. These parameters can be found on the specification sheet for a transistor. h i = input resistance h r = reverse transfer voltage ratio (V i /V o ) 0 h f = forward transfer current ratio (I o /I i ) h o = output conductance 8
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Simplified General h-Parameter Model h i = input resistance h f = forward transfer current ratio (I o /I i ) 9
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r e vs. h-Parameter Model ac fe e ie h r h Common-Emitter Common-Base 1 h r h fb e ib 10
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The Hybrid Model The hybrid model can be approximated by the r e parameters. 11
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Common-Emitter Fixed-Bias Configuration The input is applied to the base The output is from the collector High input impedance Low output impedance High voltage and current gain Phase shift between input and output is 180 12
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Common-Emitter Fixed-Bias Configuration AC equivalent r e model 13
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Common-Emitter Fixed-Bias Calculations C o 10R r e C v e o C i o v r R A r ) r || (R V V A e B C o r 10 R , 10R r i e B C o o B i o i A ) r )(R R (r r R I I A C i v i R Z A A Current gain from voltage gain: Input impedance: Output impedance: Voltage gain: Current gain: e E r 10 R e i e B i r Z r || R Z C o O R 10 r C o C o R Z r || R Z 14
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Common-Emitter Voltage-Divider Bias r e model requires you to determine , r e , and r o . 15
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Common-Emitter Voltage-Divider Bias Calculations Current gain from voltage gain: Input impedance: Output impedance: Voltage gain: Current gain: e i 2 1 r || R Z R || R R C o 10R r C o o C o R Z r || R Z C o 10R r e C i o v e o C i o v r R V V A r r || R V V A e C o C o r 10 R , 10R r i o i 10R r e i o i e C o o i o i I I A r R R I I A ) r R )( R (r r R I I A C i v i R Z A A 16
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Common-Emitter Emitter-Bias Configuration 17
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Impedance Calculations E b E e b E e b b B i R Z ) R (r Z 1)R ( r Z Z || R Z C o R Z Input impedance: Output impedance: 18
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Gain Calculations Current gain from voltage gain: Voltage gain: Current gain: E b E e b R Z E C i o v ) R (r Z E e C i
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  • Spring '17
  • Alternating Current, Input impedance, Impedance matching, Electrical parameters, BJT Transistor Modeling

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