Bipolar Junction Transistor
Minority carrier distributions and
evaluation of terminal currents.
, Diffusion Eqn. in base region
• To analyze the terminal currents, the excess hole
concentrations at both sides of the base to be determined.
, Diffusion Eqn. in base region
• The excess hole concentrations at both sides of the base
is given by the equations
• Emitter jn. Is strongly forward biased and collector base
jn. Is strongly reverse biased. So the above eqn. becomes
, Diffusion Eqn. in base region
• Excess hole concentration as a function of distance in the
base δp(xn) by using proper boundary conditions in the
diffusion eqn.
• The solution of this equation is
Minority carrier distributions and
evaluation of terminal currents.
, Diffusion Eqn. in base region
• To analyze the terminal currents, the excess hole
concentrations at both sides of the base to be determined.
, Diffusion Eqn. in base region
• The excess hole concentrations at both sides of the base
is given by the equations
• Emitter jn. Is strongly forward biased and collector base
jn. Is strongly reverse biased. So the above eqn. becomes
, Diffusion Eqn. in base region
• Excess hole concentration as a function of distance in the
base δp(xn) by using proper boundary conditions in the
diffusion eqn.
• The solution of this equation is
