Question

In the circuit shown in figure, when the input voltage of the base resistance is 10 V, V_be is zero and V_ce is also zero. Find the values of I_b, I_c and β.

Answer 1

According to the problem, V_i = 10 V, Resistance, R_B = 400 kΩ, V_BE = 0, V_CE = 0 and R_C = 3 kΩ

${\displaystyle V_i-V_{BE}=R_B{I}_B}$

${\displaystyle I_B=\frac{\text{Voltage across} R_B}{R_B}}$

= ${\displaystyle \frac{10}{400\times {10}^3}}$

= ${\displaystyle 25\times {10}^{-6}}$ A

= 25 μA

Voltage across R_C = 10 V

${\displaystyle V_{ℂ}-V_{CE}=I_C{R}_C}$

${\displaystyle I_C=\frac{\text{Voltage across} R_C}{R_C}}$

= ${\displaystyle \frac{10}{3\times {10}^3}}$

= ${\displaystyle 3.33\times {10}^{-3}}$ A

= 3.33 mA

β = ${\displaystyle \frac{I_C}{I_B}}$

= ${\displaystyle \frac{3.33\times {10}^{-3}}{25\times {10}^{-6}}}$

= ${\displaystyle 1.33\times {10}^2}$

= 133