Question
How is an LED biased when emitting light?
Answer Options
- A) In the tunnel-effect region
- B) At the Zener voltage
- C) Reverse biased
- D) Forward biased
Correct Answer: D
Explanation
An LED (Light-Emitting Diode) is a semiconductor device that produces light when current flows through it. As a diode, it requires a positive voltage on the anode and a negative voltage on the cathode to permit current flow.
Therefore, an LED is forward biased when emitting light. When the forward-bias voltage is sufficient to overcome the diode’s threshold voltage, electrons combine with holes in the semiconductor material, releasing energy in the form of photons (light).
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