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[citation needed] For example, the internal structure of an NPN bipolar transistor resembles two P-N junction diodes connected together by a common anode. In normal operation the base-emitter junction does indeed form a diode, but in most cases it is undesirable for the base-collector junction to behave as a diode.
Ebers–Moll model for an NPN transistor. [28] I B, I C and I E are the base, collector and emitter currents; I CD and I ED are the collector and emitter diode currents; α F and α R are the forward and reverse common-base current gains. Ebers–Moll model for a PNP transistor Approximated Ebers–Moll model for an NPN transistor in the ...
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.
p–n junctions represent the simplest case of a semiconductor electronic device; a p-n junction by itself, when connected on both sides to a circuit, is a diode. More complex circuit components can be created by further combinations of p-type and n-type semiconductors; for example, the bipolar junction transistor (BJT) is a semiconductor in ...
The circuit can be explained by viewing the transistor as being under the control of negative feedback. From this viewpoint, a common-collector stage (Fig. 1) is an amplifier with full series negative feedback. In this configuration (Fig. 2 with β = 1), the entire output voltage V out is placed contrary and in series with the input voltage V in.
Alternately, if a germanium PNP device was used, it would have significantly different characteristics than the silicon NPN transistor. In the quasi-complementary topology, the performance of the lower pull pair, which uses a single NPN transistor, more closely matches the performance of the upper push pair, which consists of two NPN ...
The BC548 is a part of a family of NPN and PNP epitaxial silicon transistors that originated with the metal-cased BC108 family of transistors.The BC548 is the modern plastic-packaged BC108; [6] the BC548 article at the Radiomuseum website [7] describes the BC548 as a successor to the BC238 and differing from the BC108 in only the shape of the package.
The NPN output could drive PNP inputs, and vice versa. "The disadvantages are that more different power supply voltages are needed, and both pnp and npn transistors are required." [9] Instead of alternating NPN and PNP stages, another coupling method employed Zener diodes and resistors to shift the output logic levels to be the same as the ...