BJT Internal Capacitances and High Frequency Model - BITS Pilani
BJT Internal Capacitances and High Frequency Model - BITS Pilani
BJT Internal Capacitances and High Frequency Model - BITS Pilani
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<strong>BJT</strong> <strong>Internal</strong> <strong>Capacitances</strong><br />
۞Transistor exhibit charge storage phenomenon that limit the<br />
speed <strong>and</strong> frequency of their operation<br />
۞These charge effects are accounted by adding capacitances<br />
to the hybrid π model.<br />
Base charging or diffusion capacitance C de<br />
۞When the transistor is operating in active or Saturation region<br />
mode, minority carrier charge is stored in the base region.<br />
۞When an npn transistor is operating in active mode, this<br />
charge Q n ia represented by<br />
Q<br />
n<br />
2<br />
W<br />
2D<br />
n<br />
i<br />
C<br />
Where<br />
W<br />
Basewidth<br />
D<br />
n<br />
Eletron Diffusivityin Base<br />
<strong>BITS</strong> <strong>Pilani</strong>, Dubai Campus
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