Category Archive for: BIPOLAR JUNCTION TRANSISTORS

TRANSISTOR TYPES RATINGS AND SPECIFICATIONS

In m xlcrn electronic circuits, discrete sransistors are used primarily for applications in -hich only one c,· a small number of devices arc required, and in applications where substantial power is dissipated. Although older designs, composed entirely of discrete devices, can still be found in large numbers, most new circuits containing a large number of transistors arc constructed in…

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THE BJT INVERTER (TRANSISTOR SWITCH

Transistors are widely used in digital logic circuits and switching applications similar to those described in Chapter 3. Recall that the waveforms encountered in those applications periodically alternate between a “low” and a “high” voltage, such as o Y and +5 Y. The fundamental transistor circuit used in switching applications is called an inverter, the NPN version of which…

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Common-Collector Bias Circuit

Figure 4-39 shows common-collector bias circuits for NPN and PNP transistors. Once again, the load line for Figure 4-39(a) can be derived by writing Kirchhoff’s voltage law around the output loop Recall that the output characteristics for the CC configuration are, for all practical purposes. the same as those for the CE configuration. Therefore. we will not present another…

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COMMON-COLLEGTOR CHARACTERISTICS

In the third and final way to arrange the biasing of a transistor, the collector is made the common point. The result is called the common-collector (CC) configuration and is illustrated in Figure 4-23. It is apparent in Figure 4-23(a) that Therefore, in order to keep the collector-base junction reverse biased (VeB > 0), it is necessary that…

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Common-Emitter Output Characteristics

Common-emitter output characteristics show collector current I( versus collector voltage Vo:, for different fixed values of 11/. These characteristics are often called collector churacteristics. Figure 4-19 shows a typical set of output characteristics for an NPt’J transistor in the CE configuration. The approximate value of the {3 of the transistor can be determined at any point on the characteristics…

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Breakdown

As is the’ case in a reverse-biased diode, the current through the collector-base junction of it transistor may increase suddenly if the reverse-biasing voltage across it is made sufficiently large. This increase in current is typically caused by the avalanching mechanism already described in connection with diode breakdown. However! in a transistor it can also be the result of…

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COMMON-BASE CHARACTERISTICS

In our introduction to the theory of transistor operation wc showed a bias circuit (Figure 4…4..) in which the base was treated as the ground, or “common” point of the circuit. In other words all voltages (collector-to-base and emitter-to-base) were referenced to the base. This bios arrangement results in what is called the base (CB) configuration for the transistor.…

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BIPOLAR JUNCTION TRANSISTORS

INTRODUCTION The workhorse of modern electronic circuits, both discrete and integrated, is the transistor. The importance of this versatile device stems from its ability to produce amplification, or gain, in a circuit. We ..say that amplification has been achieved when a ..  circuits. As a means fOr creating gain. the transistor is in many ways analogous to a small…

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