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Shockley Diode Model

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The Shockley diode equation is an approximation that relates the diode’s current to its voltage.

$$ I = I_S \cdot (e^{\frac{V_D}{nV_T}} - 1)$$

Where

  • \(\small I\) is the current through the diode
  • \(\small I_S\) is the diode’s saturation current
  • \(\small V_D\) is the diode’s voltage
  • \(\small n\) is the diode’s ideality factor, usually between 1 and 2
  • \(\small V_T\) is the thermal voltage, which is equal to \(\small kT/q\) where \(\small k\) is Boltzmann’s constant, \(\small T\) is the temperature in Kelvin, and \(\small q\) is the electron charge.

When \(\small V_D\) is large relative to \(\small nV_T\), the equation can be approximated as:

$$ I \approx I_S \cdot e^{\frac{V_D}{nV_T}} $$

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