The I-V characteristic of an LED is :

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Physics

Energy Bands and Types of Semiconductor

PN Junction Diode

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Question

The I-V characteristic of an LED is :

LED is working only in forward biased condition.

∴ I - V characteristics will be forward I - V characteristics of a diode. therefore option C is correct.

An LED (Light Emitting Diode) is a semiconductor device that emits light when current flows through it. Its I-V (current-voltage) characteristic is similar to a standard diode but with a higher forward voltage drop (typically 1.8-3.3V depending on the material).

Key features of LED I-V characteristic:

No current flows below the threshold voltage (reverse bias and small forward bias)
Current increases exponentially once the forward voltage exceeds the threshold voltage
The curve is non-linear and very steep after the threshold voltage
In reverse bias, only a very small leakage current flows until breakdown

The correct I-V characteristic shows:

Very little current for voltages below threshold
Rapid exponential increase in current beyond threshold voltage
The curve is shifted to the right compared to silicon diodes (higher threshold voltage)
Asymmetrical behavior between forward and reverse bias

The threshold voltage V_th can be calculated using the diode equation:

I = I_{s} (e^{\frac{qV}{ηkT}} - 1)

where I is current, I_s is reverse saturation current, q is electron charge, V is voltage, η is ideality factor, k is Boltzmann's constant, and T is temperature.

Important Formulae

Diode equation: $I = I_{s} (e^{\frac{qV}{ηkT}} - 1)$

Energy of emitted photons: $E = h ν = \frac{hc}{λ}$

where h is Planck's constant, ν is frequency, c is speed of light, and λ is wavelength.

Detailed Solution

Related Topics

Important Formulae

Detailed Solution

Related Topics

Important Formulae

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