Discussion
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- Question
Secondary emission is always decremental.
Options- A. True
- B. False
- Correct Answer
- False
ExplanationSometimes it can be useful also.
Electronic Devices and Circuits problems
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- 1. A potential of 7 V is applied to a silicon diode. A resistance of 1 K ohm is also in series with the diode. The current is
Options- A. 7 mA
- B. 6.3 mA
- C. 0.7 mA
- D. 0 Discuss
Correct Answer: 6.3 mA
Explanation:
- 2. At very high temperatures the extrinsic semi conductors become intrinsic because
Options- A. drive in diffusion of dopants and carriers
- B. band to band transition dominants over impurity ionization
- C. impurity ionization dominants over band to band transition
- D. band to band transition is balanced by impurity ionization Discuss
Correct Answer: band to band transition dominants over impurity ionization
Explanation:
Covalent bonds are broken.- 3. The word enhancement mode is associated with
Options- A. tunnel diode
- B. MOSFET
- C. JFET
- D. photo diode Discuss
Correct Answer: MOSFET
Explanation:
MOSFET may be depletion mode or enhancement mode.- 4. In a bipolar transistor the barrier potential
Options- A. 0
- B. a total of 0.7 V
- C. 0.7 V across each depletion layer
- D. 0.35 V Discuss
Correct Answer: 0.7 V across each depletion layer
Explanation:
Since there are two p-n junctions, there are two depletion layers and 0.7 V across each layer.- 5. When a voltage is applied to a semiconductor crystal then the free electrons will flow.
Options- A. towards positive terminal
- B. towards negative terminal
- C. either towards positive terminal or negative terminal
- D. towards positive terminal for 1 ?s and towards negative terminal for next 1 ?s Discuss
Correct Answer: towards positive terminal
Explanation:
Since electrons are negatively charged they will flow towards positive terminal.- 6. The number of doped regions in PIN diode is
Options- A. 1
- B. 2
- C. 3
- D. 1 or 2 Discuss
Correct Answer: 2
Explanation:
A PIN diode has p and n doped regions separated by intrinsic layer.- 7. In an n channel JFET, the gate is
Options- A. n type
- B. p type
- C. either n or p
- D. partially n & partially p Discuss
Correct Answer: p type
Explanation:
Since channel is n type gate must be p type.- 8. Recombination produces new electron-hole pairs
Options- A. True
- B. False Discuss
Correct Answer: False
Explanation:
Due to recombination the number of electron-hole pairs is reduced.- 9. A silicon (PN) junction at a temperature of 20°C has a reverse saturation current of 10 pico Ampere. The reverse saturation current at 40°C for the same bias is approximately.
Options- A. 30 pA
- B. 40 pA
- C. 50 pA
- D. 60 pA Discuss
Correct Answer: 40 pA
Explanation:
By increasing of temperature by 10°C, Io become double so by increasing temperature 20°C, Io become 4 time than initial value... and it is 40 PA.- 10. Ferrite have
Options- A. low copper loss
- B. low eddy current loss
- C. low resistivity
- D. higher specific gravity compared to iron Discuss
Correct Answer: low resistivity
Explanation:
Ferrite is a low density material of composition with Fe2O3 x O, where x is a bivalent metal, such as Cobart, Ni, Mn. These magnetic materials having very low loss of current and used in high frequency circuit.
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