Tag: zener diode

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Questions Related to zener diode

Multiple choice zener diode special purpose diodes electronic devices semiconductor electronics: materials, devices and simple circuits physics

At breakdown voltage, the rate of creation of hole-electron pairs is _____  leading to the _______  in current. 

  1. increased, decrease

  2. increased, increase

  3. decreased, increase

  4. decreased, decrease
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When the reverse voltage across a diode is very large, the valance electrons become free due to applied high electric field and get enough acceleration to make other electrons free, thus create a lot of electron-hole pairs in a short time. As the number of charge carriers increases, current also increases.

Therefore, at breakdown voltage, the rate of creation of hole-electron pairs is increased leading to the increase in current.

Multiple choice zener diode special purpose diodes electronic devices semiconductor electronics: materials, devices and simple circuits physics

Which of these is the best description of a Zener diode ?

  1. It is a constant voltage device.

  2. It operates in the reverse region.

  3. It is a constant current device.

  4. It works in forward region.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Zener diode is a p-n junction diode working in the breakdown region. It is used as a voltage regulator/stabilizer to provide a constant voltage from a source whose voltage may fluctuate over a wide range.

Multiple choice zener diode special purpose diodes electronic devices semiconductor electronics: materials, devices and simple circuits physics

Zener-diode is used in.

  1. Amplification

  2. Rectification

  3. Oscillator in producing oscillations

  4. Volatge regulation
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

 A voltage regulator circuit can be designed using a zener diode to maintain a constant DC output voltage across the load in spite of variations in the input voltage or changes in the load current. 

Multiple choice zener diode special purpose diodes electronic devices semiconductor electronics: materials, devices and simple circuits physics

 If the series resistance decreases in an unloaded zener regulator, the zener current

  1. Decreases

  2. Stays the same

  3. Increases

  4. Equals the voltage divided by the resistance
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

current increases as the resistance decreases, as zener current is inversely proportional to the series resistance

Multiple choice zener diode special purpose diodes electronic devices semiconductor electronics: materials, devices and simple circuits physics

Zener diodes with breakdown voltage ranging over 2V- 200 V are commercially available. Breakdown voltage of a zener diode

  1. Increases with increasing doping concentration

  2. Decreases with increasing doping concentration

  3. Does not depend on doping concentration

  4. May increases or decreases with increasing doping concentration
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

For Zener Diodes, the breakdown voltage decreases with increasing doping concentration.

Multiple choice zener diode special purpose diodes electronic devices semiconductor electronics: materials, devices and simple circuits physics

A zener diode is specified as having a breakdown voltage of $9.1 V$, with a maximum power dissipation of $364 \ mW$. What is the maximum current the diode can handle? 

  1. $40 \ mA$
  2. $60 \ mA$
  3. $50 \ mA$
  4. $45 \ mA$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Maximum power dissipation is the product of breakdown voltage and maximum current. Dividing the maximum power by the Zener voltage yields I_max = P / V_z = 364 mW / 9.1 V = 40 mA. Thus, option A is the correct choice.