Question

In given transistor circuit at saturation mode, $V_{BE}=0.8V,V_{CE}=0.2V$ and $\beta =100$ , then the required value of $R_C$ for which transistor remains in saturation mode, will be:-

• A. $2.31k\Omega$
• B. $4.67k\Omega$
• C. $5.32k\Omega$
• D. $6.24k\Omega$

Answer 1

Answer: (B)

in base emitter loop
$5-\left(200k\right)i_B-0.8=0$
$i_B=\frac{5-0.8}{200\times 10^3}$
$i_B=\frac{4.2}{2\times 10^5}=2.1\times 10^{-5}$
$\beta =\frac{i_C}{i_B}\Rightarrow i_C=\beta i_B=100\times 2.1\times 10^{-5}$
$=2.1\times 10^{-3}$ Amp.
$V_{CC}-R_C{i}_c-0.2=0$
$R_C=\frac{V_{CC}-0.2}{i_C}=\frac{10-0.2}{2.1\times 10^{-3}}=4.67k\Omega$