Question

The current voltage relation of diode is given by $I=(e^{1000V/T}-1)$ mA, where the applied voltage V is in volts and the temperature T is in degree Kelvin. If a student makes an error measuring $\pm$ 0.01V while measuring the current of 5mA at 300 K, what will be the error in the value of current in mA?

• A. 0.5 mA
• B. 0.05 mA
• C. 0.2 mA
• D. 0.02 mA

Answer 1

The correct option is C 0.2 mA

$5=e^{1000\frac{V}{T}}-1$
$\Rightarrow e^{1000}\frac{V}{T}=6$ (1)
Again, $I=e^{1000}\frac{V}{T}-1$
$\frac{dI}{dV}=e^{\frac{1000V}{T}}\frac{1000}{T}$
$dI=\frac{1000}{T}{e}^{\frac{1000}{T}V}dV$
Using (1)
$\Delta =\frac{1000}{T}\times 6\times 0.01=\frac{60}{300}=0.2mA$