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If the gate voltage is below the threshold voltage (left figure), the "enhancement-mode" transistor is turned off and ideally there is no current from the drain to the source of the transistor. In fact, there is a current even for gate biases below the threshold ( subthreshold leakage ) current, although it is small and varies exponentially ...
Early, is the variation in the effective width of the base in a bipolar junction transistor (BJT) due to a variation in the applied base-to-collector voltage. A greater reverse bias across the collector–base junction, for example, increases the collector–base depletion width, thereby decreasing the width of the charge carrier portion of the ...
Shockley derives an equation for the voltage across a p-n junction in a long article published in 1949. [2] Later he gives a corresponding equation for current as a function of voltage under additional assumptions, which is the equation we call the Shockley ideal diode equation. [3]
Frequency compensation for general purpose operational amplifiers and transistor Miller integrator are examples of useful usage of the Miller effect. The op-amp inverting amplifier is a typical circuit, with parallel negative feedback, based on the Miller theorem, where the op-amp differential input impedance is apparently decreased to zero
Full hybrid-pi model. The full model introduces the virtual terminal, B′, so that the base spreading resistance, r bb, (the bulk resistance between the base contact and the active region of the base under the emitter) and r b′e (representing the base current required to make up for recombination of minority carriers in the base region) can be represented separately.
In semiconductor electronics, Dennard scaling, also known as MOSFET scaling, is a scaling law which states roughly that, as transistors get smaller, their power density stays constant, so that the power use stays in proportion with area; both voltage and current scale (downward) with length.
Johnson's figure of merit is a measure of suitability of a semiconductor material for high frequency power transistor applications and requirements. More specifically, it is the product of the charge carrier saturation velocity in the material and the electric breakdown field under same conditions, first proposed by Edward O. Johnson of RCA in 1965.
In the bipolar transistor example, it is the ratio of the output current to the input current, both measured in amperes. In the case of other devices, the gain will have a value in SI units. Such is the case with the operational transconductance amplifier , which has an open-loop gain ( transconductance ) in siemens ( mhos ), because the gain ...