Name: Transistor Parameters
Uploaded: 2019-07-19
Duration: 11 min 25 s
Description: This video explains how to calculate the parameters of transistors such as current gain, voltage gain and power gain in CE configuration. View this to learn more.

Question

Explain input and output characteristics of a common emitter transistor and obtain expression for current gain and input resistance and output resistance.

Accepted Answer

Common emitter characteristics. The circuit diagram for common emitter p-n-p transistor is shown . The input is applied across the emitter and base and output is taken across collector and emitter. Here emitter is common to both input and output circuits. The most important characteristics of common base connections are input characteristic and output characteristics

Input Characteristics: The curve describes the changes in the values of input current with respect to the values of input voltage keeping the output voltage constant.

Output Characteristics: The curve is got by plotting the output current against output voltage keeping the input current constant.

(1) Output characteristics of n-p-n transistor.

Input characteristics on n-p-n transistor

A.c current gain = it is defined as the ratio of change in collector current to the change emitter current at constant collector voltage.

$β = \frac{I_{C}}{I_{B}}$ ...................................................................(1)

where $I_{C}$ = change in collector current and $I_{B}$ = change in base current

Input resistance = $\frac{input voltage}{input current} = \frac{V_{EE}}{I_{B}}$ .........................................(2)

Output resistance = $\frac{output voltage}{output current} = \frac{V_{CC}}{I_{C}}$ ..................................(3)

Explain input and output characteristics of a common emitter transistor and obtain expression for current gain and input resistance and output resistance.

Important Questions on Junction Transistors

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