Q.
The junction diode in the following circuit requires a minimum current of 1mA to be above the knee point (0.7 V) of its $I - V$ characteristic curve. The voltage across the junction diode is independent of current above the knee point, if $V_{B}\text{=}4V$, then the maximum value of $R$ so that the voltage is above knee point will be
A) $3.3\ k\Omega$
B) $4.0\ k\Omega$
C) $4.7\ k\Omega$
D) $6.6\ k\Omega$
Explanation
(a) $V_{B} = V_{knee} + IR$
or $4 = 0.7 + 10^{- 3}\ R$
or $R = 3.3/10^{- 3} = 3.3 \times 10^{3}\Omega$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.