Diodeligningen

Diodeligningen, also known as the Shockley diode equation, is a fundamental equation in semiconductor physics that describes the current-voltage (I-V) characteristics of an ideal diode. Developed by William Shockley, it provides a mathematical model for the behavior of a p-n junction diode under various operating conditions, including forward bias, reverse bias, and zero bias.

The equation is typically expressed as: I = Is * (e^(Vd / (n * Vt)) - 1), where I represents the diode current, Is is the reverse saturation current, Vd is the voltage across the diode, n is the ideality factor, and Vt is the thermal voltage. The ideality factor (n) accounts for non-ideal behaviors, with a value of 1 representing a theoretically perfect diode and values greater than 1 indicating increased recombination in the depletion region or other imperfections. The thermal voltage (Vt) is dependent on temperature and is calculated as kT/q, where k is Boltzmann's constant, T is the absolute temperature in Kelvin, and q is the elementary charge.

In forward bias (Vd > 0), the exponential term dominates, leading to a rapid increase in current as the voltage increases. In reverse bias (Vd < 0), the exponential term becomes very small, and the current is approximately equal to -Is, a small negative current. At zero bias (Vd = 0), the current is zero. The diodeligningen is crucial for understanding and designing electronic circuits that utilize diodes, such as rectifiers, amplifiers, and logic gates.

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