Physics Electronics PMDC Conceptual Practice
PMDC Verified Question 444 of 494
If the reverse saturation leakage current of a silicon diode is \( 10\text{ nA} \) at \( 25^\circ\text{C} \), what is its approximate value at \( 55^\circ\text{C} \)?
A
\( 30\text{ nA} \)
B
\( 80\text{ nA} \)
C
\( 40\text{ nA} \)
D
\( 160\text{ nA} \)
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: \( 80\text{ nA} \)
Concept:

The reverse saturation current approximately doubles for every \( 10^\circ\text{C} \) increase in operating temperature.

Formula:

$$I_0(T_2) = I_0(T_1) \times 2^{\frac{\Delta T}{10}}$$

Solution:

  • Calculate temperature change: \( \Delta T = 55^\circ\text{C} - 25^\circ\text{C} = 30^\circ\text{C} \).


  • Calculate number of \( 10^\circ\text{C} \) doublings: \( n = \frac{30}{10} = 3 \).


  • Calculate leakage current:


  • $$I_0(55^\circ\text{C}) = 10\text{ nA} \times 2^3 = 10\text{ nA} \times 8 = 80\text{ nA}$$


Why other options are incorrect:

  • Option A: \( 30\text{ nA} \) assumes a linear increase (\( 10 + 30 \)) rather than exponential doubling.
  • Option C: \( 40\text{ nA} \) corresponds to two doublings (\( 20^\circ\text{C} \) rise to \( 45^\circ\text{C} \)).
  • Option D: \( 160\text{ nA} \) corresponds to four doublings (\( 40^\circ\text{C} \) rise to \( 65^\circ\text{C} \)).

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