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Thus for example a NPN gate driven by a PNP gate would see the threshold voltage of -6V in the middle of the range of 0V to -12V. Similarly for the PNP gate switching at 0V driven by a range of 6V to -6V. The 1401 used germanium transistors and diodes in its basic gates. [7] The 1401 also added an inductor in series with R2.
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 expressions are derived for a PNP transistor. For an NPN transistor, n has to be replaced by p, and p has to be replaced by n in all expressions below. The following assumptions are involved when deriving ideal current-voltage characteristics of the BJT [7] Low level injection; Uniform doping in each region with abrupt junctions
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 ...
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 ...
The most common BJTs are NPN and PNP type. NPN transistors have two layers of n-type semiconductors sandwiching a p-type semiconductor. PNP transistors have two layers of p-type semiconductors sandwiching an n-type semiconductor. Field-effect transistors (FET) are another type of transistor which amplify current implementing extrinsic ...
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 current source transistor may be replaced with a resistor from the positive supply to the base of the inverter transistor, since discrete resistors are smaller and less expensive than discrete transistors. Similarly, the merged PNP current injector transistor and the NPN inverter transistor can be implemented as separate discrete components.