V-I characteristics of a silicon diode is shown. The ratio of resistance of diode at ID=15 mA and VD=-10 V, is

Question

V-I characteristics of a silicon diode is shown. <img class="img-fluid question-image" alt="image" src="https://cdn.tardigrade.in/img/question/physics/ee3b7f4f423c3a315354869c00b92ff6-.png" /> The ratio of resistance of diode at ID=15 mA and VD=-10 V, is (A) 10-3 (B) 10-4 (C) 10-5 (D) 10-6

Tardigrade Admin · Accepted Answer

From the graph, at I=20 mA V=0.8 V and I=10 mA , V=0.7 V rF B=(Δ V/Δ I)=(0.1 V /10 mA )=10 Ω Also, at V=-10 V , I=-1 μ A rR B=(10 V /1 μ A )=1 × 107 Ω ∴ Ratio =(rF B/rR B)=(10/107)=10-6

Q. $V - I$ characteristics of a silicon diode is shown.

The ratio of resistance of diode at $I_{D} = 15 m A$ and $V_{D} = - 10 V$ , is

$1 0^{- 3}$

$1 0^{- 4}$

$1 0^{- 5}$

$1 0^{- 6}$

From the graph, at $I = 20 m A$
$V = 0.8 V$
and $I = 10 m A, V = 0.7 V$
$r_{FB} = \frac{Δ V}{Δ I} = \frac{0.1 V}{10 m A} = 10 Ω$
Also, at $V = - 10 V, I = - 1 μ A$
$r_{RB} = \frac{10 V}{1 μ A} = 1 \times 1 0^{7} Ω$
$∴$ Ratio $= \frac{r _{FB}}{r _{RB}} = \frac{10}{1 0 ^{7}} = 1 0^{- 6}$

Q. V−I characteristics of a silicon diode is shown. The ratio of resistance of diode at ID​=15mA and VD​=−10V, is

10−3

10−4

10−5

10−6