10 Aug The Ebers-Moll Model is an electronic representation of a transistor, either NPN or PNP, in any of the four fundamental configurations. Figure: The Ebers-Moll Model of an n-p-n Bipolar Junction Transistor Two dependent current sources are used to indicate the interaction of the junctions. The PNP Bipolar Transistor block uses a variant of the Ebers-Moll equations to represent an PNP bipolar transistor.

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Ebers Moll Equations

Wikimedia Commons has media related to Bipolar junction transistors. Early voltage effect Optional base, collector, and emitter resistances.

Retrieved from ” https: This helps prevent numerical issues associated with the steep gradient of the exponential function e x at large values of x. It is this gain that allows BJTs to be used as the building blocks of electronic amplifiers.

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Zero bias base resistance RB Resistance at the base at zero bias. Since D1 and D2 are in series same current should flow through both of them then only currents order of reverse saturation currents flow through their junctions. Ideal maximum reverse current gain.

The default value is 1. Base current when the base-emitter voltage is Vbe. An NPN transistor comprises two semiconductor junctions that share mooll thin p-doped region, and a PNP transistor comprises two semiconductor junctions that share a thin n-doped region. The reason the ebers moll model of transistor is heavily doped ebers moll model of transistor to increase the emitter injection efficiency: This is the saturation current value used in the bipolar transistor equations when temperature dependence is modeled.


Detailed transistor models of transistor action, such as the Gummel—Poon modelaccount for the distribution of this charge explicitly to explain transistor behaviour more exactly. The base internal current is mainly by diffusion see Fick’s law and. By design, most of the BJT collector current is ebers moll model of transistor to the flow of charge carriers electrons or holes injected from a high-concentration emitter into the base where they are minority carriers that diffuse toward the collector, and so BJTs are classified as minority-carrier devices.

The default value is 1e A. A significant minority are also now made from gallium arsenideespecially for very high speed applications see HBT, below. The common-base current ebers moll model of transistor is approximately the gain of current from emitter to collector in the forward-active region.

For more information on using thermal ports and on the Thermal Port tab parameters, see Simulating Thermal Effects in Semiconductors. I B and I C are base and collector currents, defined as positive into the device. Transistor Manual 6th ed.

The regions of a BJT are called emittercollectorand base. These have been addressed in various more advanced models: The normal mode of operation corresponds to the use of emitter as source of collector current and inverted mode of operation corresponds to ebers moll model of transistor use of collector as source of emitter current which is the case when BJT is operated in inverse active region.

The ebers moll model of transistor runaway process associated with secondary breakdown, once triggered, occurs almost instantly and may catastrophically damage the transistor package. Simplified cross section of a planar NPN bipolar junction transistor. Modeling Temperature Dependence The default behavior is that dependence on temperature is not modeled, and the device is simulated at the temperature for which you provide block parameters.

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Darlington transistor Sziklai pair Cascode Long-tailed pair. Analogue and digital electronics for engineers. IS Ts is the saturation current at the simulation temperature. The collector—base junction is reverse biased in normal operation.


The collector current in a BJT when operated in normal mpdel is given as. Now coming to important question of Why two back to back diodes cannot function as a transistor? Retrieved August ebers moll model of transistor, The default value is -5 V. To minimize the fraction of carriers that recombine before reaching the collector—base junction, the transistor’s base region must be thin enough that carriers can diffuse across it in much less time than the tranisstor minority-carrier lifetime.

File:Ebers-Moll model schematic (PNP).svg

The Art of Electronics 2nd ed. In typical operation, the base—emitter junction is forward-biasedwhich means that the p-doped side of the junction is at a more positive potential than the n-doped side, and the base—collector junction is reverse-biased.

Use the thermal port to simulate the effects of generated heat and device temperature. The device thus loses all gain when in this state. Click here to see To view all translated materials including this page, select Country from the ebrs navigator on the bottom of this page.