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Home » In a p-n junction diode, the current I can be expressed aswhere is called the reverse saturation current, is the voltage across the diode and is positive for forward bias and negative for reverse bias, and I is the current through the diode, is the Boltzmann constant and is the absolute temperature. If for a given diode and , then(a) What is the dynamic resistance?(b) What will be the current if reverse bias voltage changes from to ?
In a p-n junction diode, the current I can be expressed as
I=I_{0} \exp \left(\frac{e V}{2 k_{B} T}-1\right)
where I_{0} is called the reverse saturation current, V is the voltage across the diode and is positive for forward bias and negative for reverse bias, and I is the current through the diode, k_{B} is the Boltzmann constant \left(8.6 \times 10^{-5} \mathrm{eV} / \mathrm{K}\right) and \mathrm{T} is the absolute temperature. If for a given diode \mathrm{l}_{0}=5 \times 10^{-12} \mathrm{~A} and \mathrm{T}=300 \mathrm{~K}, then
(a) What is the dynamic resistance?
(b) What will be the current if reverse bias voltage changes from 1 \mathrm{~V} to 2 \mathbf{V} ?
CBSE | Class 12 | NCERT | Physics | Semiconductor Electronics: Materials, Devices and Simple Circuits
In a p-n junction diode, the current I can be expressed as
I=I_{0} \exp \left(\frac{e V}{2 k_{B} T}-1\right)
where I_{0} is called the reverse saturation current, V is the voltage across the diode and is positive for forward bias and negative for reverse bias, and I is the current through the diode, k_{B} is the Boltzmann constant \left(8.6 \times 10^{-5} \mathrm{eV} / \mathrm{K}\right) and \mathrm{T} is the absolute temperature. If for a given diode \mathrm{l}_{0}=5 \times 10^{-12} \mathrm{~A} and \mathrm{T}=300 \mathrm{~K}, then
(a) What is the dynamic resistance?
(b) What will be the current if reverse bias voltage changes from 1 \mathrm{~V} to 2 \mathbf{V} ?

The expression for current in a p-n junction diode, is given as

I=I_{0} \exp \left(\frac{e V}{2 k_{B} T}-1\right)

Here, l_{0}=5 \times 10^{-12} \mathrm{~A}

\mathrm{T}=300 \mathrm{~K}

\mathrm{k}_{\mathrm{B}} is the Boltzmann constant with a value of 8.6 \times 10^{-5} \mathrm{eV} / \mathrm{k}=8.6 \times 10^{-5} \times 1.6 \times 10^{-19}=1.376 \times 10^{-23} \mathrm{~J} / \mathrm{K}

(a) Dynamic resistance = Change in voltage/ Change in current
=0.1 / 1.23

=0.081 \Omega

(b) The current will nearly always be equal to I_{o} if the reverse bias voltage is changed from 1V to 2V. As a result, with the reverse bias, the dynamic resistance will be infinite.

i

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