Shortcut Methods

Shortcut Methods and Tricks

1. Integer values:

  • V0=0.7V for Si PNjunction
  • V0=0.3V for Ge PNjunction
  • Depletion width W=104cm for Si P-N junction
  • Depletion width W=103cm for Ge P-N junction
  • Drift Velocity vd=107 cm/s

2. Conceptual understandings:

  • Drift current is indeed proportional to the applied voltage.
  • Barrier potential V0 is indeed temperature-dependent.
  • The depletion region width does increase with increasing reverse bias voltage.
  • The electric field in the depletion region is indeed uniform.
  • The electric potential is constant in the neutral regions, as we expect.
  • The potential difference across the junction is equal to the sum of the built-in potential and the applied bias voltage.
  • The current-voltage characteristic of a PN junction diode is indeed nonlinear.
  • The diode is said to be forward biased when the PN junction is connected to a battery with the positive terminal connected to the P-side and the negative terminal connected to the N-side, and reverse biased when the PN junction is connected to a battery with the positive terminal connected to the N-side and the negative terminal connected to the P-side.
  • The diode is said to be in the breakdown region when the reverse bias voltage exceeds a certain value, called the breakdown voltage, just as you said.


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