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In a diode model two diodes are connected back-to-back to make a PNP or NPN bipolar junction transistor (BJT) equivalent. This model is theoretical and qualitative. This model is theoretical and qualitative.
The bipolar junction transistor, the first type of transistor to be mass-produced, is a combination of two junction diodes and is formed of either a thin layer of p-type semiconductor sandwiched between two n-type semiconductors (an n–p–n transistor), or a thin layer of n-type semiconductor sandwiched between two p-type semiconductors (a p ...
Figure 3: PNP version of the emitter-follower circuit, all polarities are reversed. A small voltage change on the input terminal will be replicated at the output (depending slightly on the transistor's gain and the value of the load resistance; see gain formula below). This circuit is useful because it has a large input impedance
The diagram shows a schematic representation of an NPN transistor connected to two voltage sources. (The same description applies to a PNP transistor with reversed directions of current flow and applied voltage.) This applied voltage causes the lower p–n junction to become forward biased, allowing a flow of electrons from the emitter into the ...
A schematic diagram of the Ebers-Moll models of a PNP BJT. The base, collector and emitter currents are I B, I C and I E, the common-base forward and reverse current gains are α F and α R, and the collector and emitter diode currents are I CD and I ED. Date: 4 August 2010, 05:26 (UTC) Source: Ebers-Moll_Model_PNP.PNG; Author
The panels show energy band diagram, electric field, and net charge density. The built-in potential of the semiconductor varies, depending on the concentration of doping atoms. In this example, both p and n junctions are doped at a 1e15 cm −3 (160 μC/cm 3) doping level, leading to built-in potential of ~0.59 volts. Reducing depletion width ...
The common base current gain (or α) of a point-contact transistor is usually around 2 to 3, [4] whereas α of bipolar junction transistor (BJT) cannot exceed 1. The common emitter current gain (or β) of a point-contact transistor does not usually exceed 1, [4] whereas β of a BJT is typically between 20 and 200. Negative differential ...
Diode–transistor logic (DTL) is a class of digital circuits that is the direct ancestor of transistor–transistor logic. It is called so because the logic gating functions AND and OR are performed by diode logic , while logical inversion (NOT) and amplification (providing signal restoration) is performed by a transistor (in contrast with ...