Leakage Current in a Transistor and Breakdown Voltage: Leakage Currents: In CB circuits shown in Fig. 10.77, if emitter current is made zero, the B-C junction still remains reverse biased and therefore, a reverse-bias leakage current exists in this junction, and this current corresponds to the reverse-bias saturation current in a diode. The direction of …
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What is BJT Beta Rule? Like transfer of primary and secondary winding impedances of a transformer, resistance from one part of a transistor circuit can be referred to another parts. For instance, resistance of collector circuit, RL can be referred to the base circuit and vice versa. Similarly resistance of emitter circuit RE may be …
DC Equivalent Circuit of Transistor: DC Equivalent Circuit of Transistor – In the common base circuit, the emitter diode acts like a forward biased ideal diode, while collector diode acts as a current source because of transistor action. Thus an ideal transistor in common-base configuration can be considered as a rectifier diode in the emitter …
Transistor approximation (Ideal, Second and Higher): An NPN transistor is shown in Fig. 10.71 (a). Voltage appearing across the emitter diode is denoted by VBE and that appearing across the collector-emitter terminals is denoted by VCE. Ideal Approximation: An ideal approximation of a transistor is shown in Fig. 10.71 (b). Emitter diode is visualized as …
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What is Thermal Runaway and Heat Sink? The maximum average power PC max which a transistor can dissipate depends upon the construction of the transistor and may lie in the range of a few milliwatts and 200 W. This maximum power is limited by the temperature that the collector-base junction withstand. For silicon transistor this …
How to use a Transistor as a Diode – Working and Equation: The transistor can be modified to operate as a diode by short circuiting the two transistor terminals, as shown in Fig. 10.69 [collector and base terminals are shorted making VCB = 0] and for a practical P-N junction if voltage across it is less …
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Transistor Lead Identification and Testing: Transistor Lead Identification and Testing – After the transistor has been manufactured, as already discussed, leads of, typically, gold, aluminium, or nickel are then attached and the entire structure is encapsulated in a container such as that given in Fig. 10.65. Those with the studs and heat sinks are high …
Transistor Load Line Analysis (DC and AC Load Line and Q Point): The concept of Transistor load line analysis is very important in understanding the working of a transistor. It is defined as the locus of operating point on the output characteristic of the transistor. It is the line on which the operating point moves …
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Transistor as an Amplifier – Circuit Diagram and Its Workings: The main utility of a transistor lies in its ability of amplifying weak signals. The weak signal is applied at the input terminals and the amplified output is obtained across the output terminals. A transistor alone cannot perform the function of amplification and some passive …
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Early Effect and Base Width Modulation: In active region, the emitter-base (EB) junction is forward biased and collector-base (CB) junction is reverse biased, so the barrier width at EB junction is negligible in comparison with the space-charge width at CB junction, as illustrated in Fig. 10.20. The transition or space-charge region at a junction is …