Electronic Devices & Logic Gates Flashcards for NEET — 20 cards

First 8 of 20 Electronic Devices & Logic Gates flashcards

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1. Card 1 of 20

   What is the truth table output of a NOR gate if BOTH inputs A and B are LOW (0)?

   Hint: NOR is NOT-OR. Since A OR B would be 0, the inversion makes it 1.

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   Answer

   Output is HIGH (1).

2. Card 2 of 20

   State the Mass Action Law for semiconductors.

   Hint: Relates the concentration of electrons, holes, and intrinsic carriers in thermal equilibrium.

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   Answer

   Where $n_e$ is electron concentration, $n_h$ is hole concentration, and $n_i$ is intrinsic carrier concentration.

3. Card 3 of 20

   What type of extrinsic semiconductor is formed when Silicon is doped with a Group 15 (pentavalent) impurity like Phosphorus?

   Hint: Pentavalent means 5 valence electrons. 4 bond with Si, 1 is 'extra'.

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   Answer

   In an n-type semiconductor, electrons are the majority charge carriers and holes are the minority charge carriers.

4. Card 4 of 20

   What type of extrinsic semiconductor is formed when Silicon is doped with a Group 13 (trivalent) impurity like Boron or Aluminum?

   Hint: Trivalent means 3 valence electrons, creating a vacancy or 'hole' in the crystal lattice.

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   Answer

   In a p-type semiconductor, holes are the majority charge carriers and electrons are the minority charge carriers.

5. Card 5 of 20

   Why is the depletion region in a p-n junction practically devoid of mobile charge carriers?

   Hint: It creates a 'barrier'.

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   Answer

   Because electrons from the n-side and holes from the p-side diffuse across the junction and recombine, leaving behind immobile ionized atoms.

6. Card 6 of 20

   What happens to the width of the depletion layer and the barrier potential in a p-n junction under Forward Bias?

   Hint: External voltage opposes the built-in potential.

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   Answer

   The width of the depletion layer decreases and the barrier potential is reduced.

7. Card 7 of 20

   What happens to the width of the depletion layer and the barrier potential in a p-n junction under Reverse Bias?

   Hint: External voltage aids the built-in potential.

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   Answer

   The width of the depletion layer increases and the barrier potential is increased.

8. Card 8 of 20

   Which two logic gates are known as 'Universal Gates'?

   Hint: They are called 'universal' because any basic logic gate (AND, OR, NOT) can be constructed using only these gates.

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   Answer

   NAND Gate and NOR Gate.