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Question: In the circuit shown here, the transistor used has a current gain \(\beta = 100\) what should be the...

In the circuit shown here, the transistor used has a current gain β=100\beta = 100 what should be the base resistor RBR_{B}so that V CE=5VCE = 5V (neglect VBEV_{BE})?

A

200×103Ω200 \times 10^{3}\Omega

B

1×106Ω1 \times 10^{6}\Omega

C

500Ω\Omega

D

2×103Ω2 \times 10^{3}\Omega

Answer

200×103Ω200 \times 10^{3}\Omega

Explanation

Solution

: Applying kirchhoff ’s law to mesh ADCEFA

VCC=10=IC×103+VCEV_{CC} = 10 = I_{C} \times 10^{3} + V_{CE}

10=IC×103+510 = I_{C} \times 10^{3} + 5

IC=5×103AI_{C} = 5 \times 10^{- 3}A ….. (i)

Applying Kirchhoff’s law to mesh AGBEFA

IB×RB+VBE=VCC=10VI_{B} \times R_{B} + V_{BE} = V_{CC} = 10V

IB×RB+0=10I_{B} \times R_{B} + 0 = 10…… (ii)

}{R_{B} = 2 \times 10^{5}\Omega }{= 200 \times 10^{3}\Omega}$$