Description : P-n junction when reversed biased acts as a (a) Capacitor (b) inductor (c) on switch (d) off switch
Last Answer : d) off switch
Description : For normal operation of a transistor, the collector base junction is kept (a) Unbiased (b) forward biased (c) reverse biased (d) none
Last Answer : (c) reverse biased
Description : On increasing the reverse bias to a large value in a p-n junction diode current (a) Increases slowly (b) Remains fixed (c) Suddenly increases (d) Decreases slowly
Last Answer : (c) Suddenly increases
Description : The capacitance of reverse biased P-N junction 1. Decreases with increasing the reverse bias 2. Increases with increasing the reverse bias 3. Depends only on reverse saturation current 4. Makes the P-N junction more effective at high frequencies
Last Answer : The capacitance of reverse biased P-N junction Decreases with increasing the reverse bias
Description : If PN junction is forward biased its resistance is (a) Zero (b) Infinity (c) A few ohm (d) A few kilo ohms
Last Answer : c) A few ohm
Description : In a reverse biased PN-junction, which current carriers cause leakage current?
Last Answer : The minority carriers
Description : Which is the most important building block of electronic devices? (a) Diode (b) p-n junction (c) transistor (d) rectifier
Last Answer : b) p-n junction
Description : Depletion region of a junction is formed _________ (a) during the manufacturing process (b) under forward bias (c) under reverse bias (d) when temperature varies
Last Answer : (a) during the manufacturing process
Description : When is a p-n junction said to be forward biased or what is meant by forward biasing of p-n junction? How does it affect resistance?
Last Answer : When the positive terminal of a cell is connected to p-side and negative terminal to the n-side of a p-n junction then it is said to be forward biased. It offers low resistance.
Description : When is a p-n junction said to be biased?
Last Answer : When an external source of e.m.f is connected to a p-n junction, it is said to be biased.
Description : When a P - N junction is forward biased 1.only electrons in N-region are injected into P-region 2.only holes in P-region are injected into N-region 3.majority carriers in each region are injected into the other region 4.minority current is reduced to zero
Last Answer : When a P - N junction is forward biased majority carriers in each region are injected into the other region
Description : A photodiode can switch its current ON or OFF in (a) nano second (b) milli second (c) micro second (d) centi second
Last Answer : (a) nano second
Description : Current gain of a transistor which has collector current of 10 mA and a base current of 40 micro Ampere is: (a) 25 (b) 250 (c) 2500 (d) 25000
Last Answer : b) 250
Description : If 1 ampere current flows through 2m long conductor the charge flow through it in 1 hour will be a. 3600C b. 7200C c. 1C d. 2C
Last Answer : a. 3600C
Description : When current of one ampere is flowing across any cross-section of wire in one second, then the quantity of charge is said to be: (a) One coulomb (b) Three coulomb (c) One micro-coulomb (d) None of above
Last Answer : (a) One coulomb
Description : The width of depletion layer of a P-N junction – (1) decreases with light doping (2) increases with heavy doping (3) is independent of applied voltage (4) is increased under reverse bias
Last Answer : (4) is increased under reverse bias Explanation: The total width of the depletion region is a function of applied reverse-bias and impurity concentration. Forward bias decreases the depletion region width whilst reverse bias increases it.
Description : The width of depletion layer of a P-N junction (1) decreases with light doping (2) increases with heavy doping (3) is independent of applied voltage (4) is increased under reverse bias
Last Answer : is increased under reverse bias
Description : Define i)P-N junction diode ii) Depletion layer iii)Forward bias iv)Reverse bias of P-N junction diode
Last Answer : i)P-N junction diode: It is a semiconductor device in which half of its region is P-type and other half is N-type. ii) Depletion layer: The region where free electrons and free holes are absent ... and negative terminal is connected to p-side of p-n junction diode, it is said to be reverse bias.
Description : A light emitting diode emits light only when (a) Reversed biased (b) forward biased (c) unbiased (d) none
Last Answer : (b) forward biased
Description : In order to reverse bias in a PN junction, what terminal of a battery is connected to the P material?
Last Answer : Negative.
Description : In p-n-p transistor, collector current is (a) Equal to emitter current (b) slightly less than emitter current (c) greater than emitter current (d) any of above
Last Answer : (c) greater than emitter current
Description : SI unit of gain of amplifier is (a) Volt (b) ampere (c) coulomb (d) dimensionless
Last Answer : (d) dimensionless
Description : The S.I Unit of Modulus elasticity is: a) Pascal b) Coulomb c) Ampere d) None
Last Answer : a) Pascal
Description : The unit Nm–2 is also called a) Coulomb b) Newton c) Pascal d) Ampere
Last Answer : c) Pascal
Description : The unit of inductance is: a. Volt b. Ampere c. Henry d. Ohm
Last Answer : c. Henry
Description : Farad is defined as: a. Coulomb / volt b. Ampere / volt c. Coulomb / joule d. Joule / Coulomb
Last Answer : d. Joule / Coulomb
Description : The SI unit of charge is: (a) Meter (b) Ampere (c) Coulomb (d) Volt
Last Answer : (c) Coulomb
Description : The SI unit of charge is: (a) Coulomb (b) Calorie (c) Ampere (d) Joule
Last Answer : a) Coulomb
Description : How do you test reverse power trip, high current trip, preferential trip?
Last Answer : Reverse power trip - refer answer for question 11. Also ask E/O. High current (over load trip) - Set your overload relay high current trip setting to say 75% of the rated current. Run the ... loads to overload the generator. Preferential trip will trip all the non-critical loads. Also ask E/O.
Description : Why is this reverse power used instead of reverse current in alternators?
Last Answer : It is extremely difficult to detect reverse current with an alternating current system, reverse power can be detected and protection can be provided by reverse power relay.
Description : The reverse current through semiconductor diode is due to (a) Minority carrier (b) majority carrier (c) electrons (d) holes
Last Answer : (a) Minority carrier
Description : A moving coil galvanometer has 150 equal divisions. Its current sensitivity is 10-divisions per milliampere and voltage sensitivity is 2 divisions per
Last Answer : A moving coil galvanometer has 150 equal divisions. Its current sensitivity is 10-divisions per milliampere and voltage ... `10^(3)` D. `10^(5)`
Description : When a PN junction is forward biased, what happens to the depletion region?
Last Answer : The depletion region decreases.
Description : Describe the working of PN junction diode with neat sketch under forward biased condition.
Last Answer : If the p-region (anode) is connected to the positive terminal of the external DC source and nside (cathode) is connected to the negative terminal of the DC source then the biasing ... The large number of majority carriers crossing the junction constitutes a current called as the forward current.
Description : For the active mode BJT operation (A) Emitter Base Junction is Forward Biased and Collector Base Junction is Forward Biased (B) Emitter Base Junction is Reverse Biased and Collector Base Junction ... Biased (D) Emitter Base Junction is Reverse Biased and Collector Base Junction is Forward Biased
Last Answer : For the active mode BJT operation Emitter Base Junction is Forward Biased and Collector Base Junction is Reverse Biased.
Description : A forward-biased PN-junction, (A) results in increase in diffusion current (B) results in increase in drift current (C) results in decrease in drift current (D) results in decrease in diffusion current
Last Answer : A forward-biased PN-junction, results in increase in diffusion current
Description : In a semiconductor diode, p-side is earthed and to n-side is applied a potential of -2 volt; the diode shall (a) Conduct (b) Not conduct (c) Conduct partially (d) Break down
Last Answer : a) Conduct
Description : In n-p-n transistor, p works as ________ (a) Collector (b) emitter (c) base (d) any of above
Last Answer : c) base
Description : A semiconductor formed by addition of trivalent impurity is : a) P–Type b) N–Type c) Q–type d) M–Type
Last Answer : d) M–Type
Description : Converting 7,000 nA into microampere will result in: A. 0.007 µA B. 0.7 µA C. 700 µA D. 7 µA
Last Answer : Converting 7,000 nA into microampere will result in: 7 µA
Description : How do you test reverse power trip?
Last Answer : When two generators are running in parallel and one generator can carry the load, reverse power trip can be tested by load shifting using governor control. When the load has shifted sufficiently and the off ... (using the test push button on the relay) to see if it initiates a trip signal.
Description : How is the protection against reverse power given?
Last Answer : Reverse power protection is used for anti-motoring. This function is used for protection of prime mover not generator. It can cut-off the fuel supply and stop the prime mover.
Description : What is the harm if reverse power flows?
Last Answer : Assume that the generator normally produces an amount of power equal to P, and that when operating as a motor, it will absorb a similar amount, P. Therefore, the net effect on the grid will ... change on the grid. There could be prime mover damage in some instances (especially steam turbines).
Description : When does Reverse power flow?
Last Answer : Situation of a generator is feeding a system through switchgear having several generators connected in parallel with this generator. The flow of current, when the system is running normally, is from the ... minor to extreme in the event of a complete mechanical failure of the generator which fails.
Description : The reverse process of photo-electric effect is called: a) Annihilation of matter b) Compton effect c) Pair production d) X-rays
Last Answer : d) X-rays
Description : The potential difference set up across the depletion region is called (a) Absolute potential (b) neutral potential (c) reverse potential (d) potential barrier
Last Answer : (d) potential barrier
Description : Process of conversion low voltage to high voltage is called _______ (a) Rectification (b)forward bias (c) reverse bias (d) amplification
Last Answer : (d) amplification
Description : In the depletion region in the P-N junction there are: a) No charges b) No current c) No mobile charges d) No electron
Last Answer : Ans: C
Description : Barrier potential in a P-N junction is caused by (A) Thermally generated electrons and holes. (B) Diffusion of majority carriers across the junction. (C) Migration of minority carriers across the junction. (D) Flow of drift current.
Last Answer : (B) Diffusion of majority carriers across the junction.
Description : Consider the following statements regarding the formation of P-N junctions: 1. Holes diffuse across the junction from P-side to N-side 2. The depletion layer is wiped out. 3. There is continuous flow of current across the junction 4 ... correct? (a) 1 and 3 (b) 2 and 3 (c) 1 and 4 (d) 2 and 4
Last Answer : Ans: (c) When a pn-junction is formed, there will be diffusion of carries across the junctions followed by recombination, and the creation of a depletion layer across which a ... potential is established, which will prevent further diffusion of carries across the junction, leading to equilibrium