Q. In the grid circuit of a triode a signal $E = 2\sqrt{2}\cos{\omega t}$ is applied. If $\mu = 14$ and $r_{p} = 10\ k\Omega$ then root mean square current flowing through $R_{L} = 12\ k\Omega$ will be

A) $1.27\ mA$
B) $10\ mA$
C) 1.5 $mA$
D) 12.4 $mA$
Explanation

(a) $A = \frac{\mu R_{L}}{r_{p} + R_{L}} = \frac{14 \times 12}{10 + 12} = \frac{84}{11}$. Peak value of output signal $V_{0} = \frac{84}{11} \times 2\sqrt{2}V$
$\Rightarrow V_{rms} = \frac{V_{0}}{\sqrt{2}} = \frac{84 \times 2}{11}V$
$\Rightarrow r.m.s.$ value of current through the load
$= \frac{84 \times 2}{11 \times 12 \times 10^{3}}A = 1.27\ mA$

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

Ph.D. in Physics with 19+ years of teaching experience.