18-04-2014, 03:13 PM
TRANSISTOR CE CHARACTERSTICS
AIM:
1. To draw the input and output characteristics of transistor connected in CE configuration
2. To find β of the given transistor.
APPARATUS:
Transistor (BC 107)
R.P.S (O-30V) 2Nos
Voltmeters (0-20V) 2Nos
Ammeters (0-200μA)
(0-500mA)
Resistors 1Kohm
Bread board
THEORY:
A transistor is a three terminal device. The terminals are emitter, base, collector. In common emitter configuration, input voltage is applied between base and emitter terminals and out put is taken across the collector and emitter terminals.
Therefore the emitter terminal is common to both input and output.
The input characteristics resemble that of a forward biased diode curve. This is expected since the Base-Emitter junction of the transistor is forward biased. As compared to CB arrangement IB increases less rapidly with VBE . Therefore input resistance of CE circuit is higher than that of CB circuit.
The output characteristics are drawn between Ic and VCE at constant IB. the collector current varies with VCE unto few volts only. After this the collector current becomes almost constant, and independent of VCE. The value of VCE up to which the collector current changes with V CE is known as Knee voltage. The transistor always operated in the region above Knee voltage, IC is always constant and is approximately equal to IB.
RESULT:
1. the input and out put characteristics of a transistor in CE configuration are Drawn
2. the of a given transistor is calculated