Question

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

• A. $200 \times 10^{3}\Omega$
• B. $1 \times 10^{6}\Omega$
• C. 500$\Omega$
• D. $2 \times 10^{3}\Omega$

Answer 1

Answer: (A)

$200 \times 10^{3}\Omega$

Answer 2

: Applying kirchhoff ’s law to mesh ADCEFA

$V_{CC} = 10 = I_{C} \times 10^{3} + V_{CE}$

$10 = I_{C} \times 10^{3} + 5$

$I_{C} = 5 \times 10^{- 3}A$ ….. (i)

Applying Kirchhoff’s law to mesh AGBEFA

$I_{B} \times R_{B} + V_{BE} = V_{CC} = 10V$

$I_{B} \times R_{B} + 0 = 10$…… (ii)

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