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Difficulty: HardDiodes

Specialized semiconductor diodes are engineered with distinct physical and electrical properties to perform specific functions in electronic circuits. Match each specialized diode and operating condition on the left with its corresponding functional characteristic or application on the right.

  • Zener diode operated beyond its reverse breakdown voltage (VZV_Z)Maintains a stable reference voltage across a circuit despite fluctuations in load current
  • Varactor (Varicap) diode operated under variable reverse biasActs as a voltage-variable capacitor primarily used in radio frequency (RF) tuning circuits
  • Schottky barrier diode in forward conductionDelivers ultra-fast switching speeds with a low forward voltage drop of approximately 0.2 V0.2\text{ V} to 0.3 V0.3\text{ V}
  • Light-Emitting Diode (LED) in forward biasConverts direct electrical current into optical radiation through electron-hole recombination

Answer

The Zener diode in reverse breakdown matches stable voltage regulation; the Varactor diode under reverse bias matches voltage-variable capacitance for RF tuning; the Schottky diode matches fast switching with low forward voltage drop; and the Light-Emitting Diode matches electroluminescent photon emission.
Each diode type corresponds to its unique semiconductor junction physics: Zener diodes maintain stable reverse breakdown voltages for regulation; varactor diodes provide voltage-dependent junction capacitance; Schottky diodes utilize metal-semiconductor junctions for high-speed switching and low forward drop; and LEDs release photons through forward-biased electron-hole recombination.

Step-by-Step Solution

1
Analyze the operational principle of the Zener diode in reverse bias.
Identified as maintaining a constant voltage (VZV_Z) across terminals.
Zener diodes are specifically doped to operate safely in the avalanche or Zener breakdown region to provide voltage regulation.
2
Analyze the operational principle of the Varactor diode under reverse bias.
Identified as a voltage-controlled variable capacitor.
The reverse bias modulates the width of the dielectric depletion region, changing junction capacitance proportionally to the applied reverse voltage.
3
Analyze the construction and forward characteristics of the Schottky barrier diode.
Identified by its metal-semiconductor junction providing low forward drop (0.2–0.3 V0.2\text{--}0.3\text{ V}) and negligible reverse recovery time.
Because majority carriers dominate conduction, there is no minority carrier recombination delay, enabling high-frequency switching.
4
Analyze the forward bias behavior of the Light-Emitting Diode (LED).
Identified as emitting light via electroluminescence.
Direct bandgap semiconductor recombination converts injected forward current into light.

Key Concept

Operating characteristics and specialized semiconductor applications of Zener, Varactor, Schottky, and Light-Emitting Diodes.
Estimated Time:1m 30s
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Topics

Diodes

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