Shockley model calculator

The Shockley model predicts the current through a diode based on the forward voltage, and the temperature of the junction. The so-called Shockley equation is:

i = IS(exp(vq/kT) - 1), where i is the forward junction current, v the forward junction bias, and T the junction temperature in Kelvins.

This model calculator assumes you have a diode in a circuit with a current-limiting resistor and a voltage supply. It assumes you know a current and voltage that represent one point along the diode's operating curve (usually from the spec sheet). We further assume approximately room temperature at the junction. Specifically we use 25°C.


Shockley diode modeler

diode parameters diode forward voltage Help
diode forward current (mA) Help
circuit parameters Source voltage Help
Resistor value Help

Of course, while the Shockley model may predict a huge current, the physical limitations of the diode will prevent your real result from getting anywhere near the model. The most interesting numbers are below the operating point you provide. The maximum continuous forward current value on your datasheet is a practical upper bound for current in your LED.

Shockley calculator version 1.0 Copyright 2006, Rob 'linear' Arnold. All rights reserved.

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