1. In an unbiased junction diode the current flow through the junction [ ]
a) Depends on the type of the material b) is not observed
c) Will be very limited d) will be very high.
2. The d.c. resistance under forward bias for a Ge diode is [ ]
a) 0.1 kΩ b) 1 kΩ c) 0.1 MΩ d) 1 MΩ
3. The reverse resistance for Ge diode is around [ ]
a) 0.1 kΩ b) 1 kΩ c) 0.1 MΩ d) 1 MΩ
4. In forward bias of a p-n junction diode [ ]
a) The current increases with voltage linearly
b) the electron from n- part are injected into p- part of the device
c ) the holes from n part are injected into p- part of the device
d) the hole from a part are injected into p part across the junction.
5. A Zener diode [ ]
a) shows extremely large reverse saturation current b) does not show any forward current
c ) possesses a sharp break down in the reverse bias d) possesses a negative resistance.
6. Under a reverse bias condition in a p- n junction diode [ ]
a) minority carriers are arrested in depletion layer b) a reverse saturation current is produced
7. c) the majority carriers diffuse across the junction d) potential drop across the diode remains constant.
8. The characteristic of a p-n junction diode is [ ]
a) it can acts as an amplifier b) it can act like an oscillator c ) it act like a rectifier
d) the cut – in voltage is the function of the forward current
9. The depletion layer in a p-n junction diode is [ ]
a) depleted of electrons b) depleted of holes c) a neutral zone
d) a charged region of positive and negative ions.
10. Zener breakdown occurs for [ ]
a) lower voltage b) higher voltage c) moderate voltage d) All voltage
11. Avalanche breakdown occurs for [ ]
a) lower voltage b) higher voltage c) moderate voltage d) All voltage
12. In an ideal p-n junction diode [ ]
a) a reverse bias does not give any current b) a reverse bias gives rise to a very high current
c) a forward bias is applied by connecting p-side to negative of the battery
d) a reverse bias is applied by connecting p side to the positive of the battery.
13. The thickness of depletion region is in the order of [ ]
a) 6 X 10 -3 cm b) 6 X 10 -9 cm c) 3 X 10-4 cm d) 3 X 10-6 cm
14. In an intrinsic semiconductor at 0 K , the fermi level lies [ ]
a) at the center of top of the valence band and bottom of the conduction band
b) at the center of donor level and bottom of the conduction band
c) at the center of donor level and intrinsic fermi level
d) at the center of acceptor level and top of the valence band
15. For silicon p-n junction, the barrier potential is about [ ]
a) 0.7 V b) 0.8 V c) 0.9 V d) 1.1 V
16. For germanium p-n junction, the barrier potential is about [ ]
a) 0.7 V b) 0.8 V c) 0.9 V d) 1.1 V
1. The opposition offered by a diode to the changing current flowing forward bias condition is known as ________________
2. The opposition offered by a diode to the direct current flowing forward bias condition is known as_________________
3. The capacitance that exists in a forward biased junction is called a_____________
4. Breakdown occurs when p-n junction diode connected in_________________
5. The voltage beyond which the current increases rapidly is called____________
6. An ordinary p-n junction should not be operated in this voltage, because the diode becomes overheat and failed due to the _______________around the junction.
7. The reverse breakdown voltage for Zener diodes decreases with an __________ in temperature.
8. An ideal diode also acts like a ________________
9. The capacitance that exists in a __________ biased junction is called a diffusion or storage capacitance.
10. In reverse breakdown region the reverse voltage across the zener diode is almost ___________of the current flowing through it.
11. Zener diode acts as a _________________.
12. The electric field intensity across a p-n junction diode _____________ as doping level are increased.
13. Before the formation of p-n junction, the fermi level lies to _______________ in p type.
14. Before the formation of p-n junction, the fermi level lies to _______________ in n type.
15. When a p-n junction is reverse biased, width of its depletion layer is ______________
1. Photo diode is used in reverse bias because [ ]
(a) Majority of hole-electron pairs swept are reversed across the junction
(b) Only one side is illuminated
(c) Reverse current is small compared to photocurrent
(d) None
2. A laser diode cav fabricated using [ ]
(a) Ge (b) Si (c) GaAr (d) None
3. When a photodiode is reverse biased and kept in dark room, the current flowing the device corresponds to [ ]
(a) Zero current (b) reverse saturation current (c) maximum current flow (d) none
4. Emission of light in an LED due to [ ]
(a) Emission of electrons (b) photo voltaic effect (c) conversion of heat into electrical energy (d)none
5. The combined package of LED and photodiode is known as
(a) Opto couplers (b) opto isolator (c) optically coupled isolated (d) all the above
6. Germanium photodiode have dark current in the order of
(a) 5mA (b) 10mA (c) 25mA (d) 10A
7. Color of an LED can be changed
(a) using different band (b) varying the doping level of semiconductor
(c) Increasing applied voltage (d) none
8. LED fabricated from gallium arsenide emit
(a) visible (b) IR (c) UV (d) none
9. The color of LED light depends on
(a) type of material (b) type of biasing (c) both (d) none
10. A laser diode
(a) produces always light of single wavelength (b) multiple wavelength (c) both (d) visible light
11. A photo diode is normally
(a) forward bias (b)reverse bias (c)none (d) emitting diode
12. When the light increases the reverse current in photodiode
(a) increase (b)decrease (c) no effect (d)none
13. What is operating voltage of LED
(a) 5-12mV (b)1.7-3.3mV (c)5-12V (d)20-25V
14. Determine the nominal voltage for the Zener diode at a temperature of 120oC if the nominal voltage is 5.1Volts at 25 oC and the temperature coefficient is 0.05%/ oC.
(a) 4.6V (b) 4.86V (c) 5.1V (d) 5.34V
15. What is the maximum power rating for LEDs?
(a)150mW (b)500mW (c)1W (d)10W
16. Light which has one single wavelength is called
(a)coherent (b)incoherent (c)neutral (d)emitter
17. Zener diode with breakdown voltage greater than 5V operate predominantly in
(a) avalanche (b) zener breakdown (c) PIN breakdown (d) varactor breakdown
18. PIN diode consist of
(a) 2 operating regions (b) 3 operating regions (c) 4 operating regions (d) 5 operating regions
19. When reverse biased, PIN diode acts as
(a) variable resistor (b) constant capacitor (c) current controlled switch (d) current controlled variable regulator
20. In PIN diode, low forward resistance of intrinsic region decreases when current
(a) increases (b) decreases (c) become constant (d) become infinite
21. When forward biased, PIN diode acts like a
(a) constant capacitor (b) variable resistor (c) current controlled variable regulator (d) current controlled switch.
22. In fiber optic systems, types of PIN diodes are used as
(a) photo detectors (b) photo resistors (c) tunner (d) transmitter.
23. Zener diode with breakdown voltages less than 5V operates predominantly in what type of breakdown?
(a)Avalanche (b) Zener (c) varactor (d) schottky.
24. The normal operating region for a zener diode is the
(a) FB region (b) RB region (c) Zero crossing (d) reverse breakdown region
25. An LED is forward-biased. The diode should be on, but no light is showing, A possible trouble might be
(a)diode open (b)series resistor is too small (c)both (d)none
26. What type of Diode maintains a constant current?
(a) LED (b) Zener (c) PN junction (d) PIN
27. Zener diodes with breakdown voltages greater than 5 V operate predominantly in what type of breakdown
(a) avalanche (b) Zener (c) PIN (d) none
28. The PIN diode must suited for _____ applications
(a) microwave oscillating (b) microwave switching (c) microwave amplifying (d) microwave rectifying
29. The PIN diode has
(a) An intrinsic layer between heavily doped P and N layers (b) B.P layer between heavily doped P and N junction (c) both (d) none of the above.
30. The main material used in the construction of PIN diodes is
(a) GaAs (b) Si (c) Ge (d) Se
31. A solar cell is an example of
(a) photo voltaic cell (b) photo conductive cell (c) photo emissive cell (d) photo radiation cell
32. Diode consist of heavily doped p and n regions separated by an intrinsic region is called
(a) zener diode (b) optical diode (c) PIN diode (d) rectifier diode
1. Visible light wavelength lying in the region _________
2. _________ generated electron hole pairs are responsible for the working of LDRs, photodiodes-optical detectors.
3. Radiative recombination associated with __________
4. Non- radiative recombination associated with _________or lattice vibration.
5. The colour or wavelength of light emitted by LED depends upon ________in GaAsP or GaP
6. LEDs are used in _________and dot matrix displays
7. Diode lasers are of size _________
8. Direct band gap semiconductors are formed by group ___________elements
9. Homojunction diode laser example ____________ laser.
10. Heterojunction lasers are __________ structures
11. Figure of merit is a measure of the target_________
12. ________is a raise in the availability of free charge carriers and the conductivity of the semiconductor.
13. _________ are devices that convert optical energy to electrical energy and use the principle internal photoelectric effect.
14. If the diode is short-circuited externally, a current flows between p and n regions. It is known as the __________mode of operation. The diode is reverse biased for photoconductive operation.
15. If the diode is left on _______ a voltage appears between p and n regions and is known as photovoltaic mode.
16. Diode under a reverse bias voltage can be used as a ______________
17. Conversion efficiency of solar cell is defined as ________
The number of carriers multiplies in geometrical progression and this phenomenon is called ________.
1. The mean value of half wave rectified sine wave is
(A) 0.707 im
(B) 0.66 im
(C) 0.5 im
(D)0.318im
2. The form factor for half wave rectified sine wave is
(A) 1.0
(B) 1.11
(C) 1.44
(D)1.57.
3. For full-wave rectified sine wave, rms value is
(A) 0.707 im
(B) 0.6036 im
(C) 0.5 im
(D)0.318im.
4. For full-wave rectified sine wave, mean value is
(A) 0.70 im
(B) 0.636 im
(C) 0.5 im
(D) 0.318 lm.
5. For full-wave rectified sine wave, form factor is
(A) 1.5
(B) 1.41
(C) 1.28
(D) 1.11.
6. A half-wave rectifier circuit with a capacitive filter is connected to a 200 Volts, 50 Hz ac line. The output voltage across the capacitor should be approximately
(A) 300 Volts (B) 280 Volts (C) 180 Volts (D) 80Volts.
7. The ripple factor of a full-wave rectifier circuit compared to that of a half wave rectifier circuit without filter is
(A) half of that for a half 'wave rectifier
(B) less than half that for a half-
wave rectifier circuit
(C) equal to that of a half wave rectifier
(D)none of the above.
8. The RMS value of a half wave rectifier current is 10 A. Its value for full wave rectification would be
(A) 10 A
(B) 14.14 A
(C) (20/π) A
(D) 20 A.
9. For single phase supply frequency of 50 Hz, ripple frequency in full wave rectifier is
(A) 25
(B) 50
(C) 100
(D) 200.
10. The dc current through each diode in a bridge rectifier equals:
(A) The load current
(B) Half the dc load current
(C) Twice the dc load current
(D) One-fourth the dc load current
11. In a power supply diagram, which block indicates a smooth dc output?
(A) Transformer
(B) Filter
(C) Rectifier
(D) Regulator
12. If a 169.7 V half-wave peak has an average voltage of 54 V, what is the average of two full-wave peaks?
(A) 119.9 V
(B) 108.0 V
(C) 115.7 V
(D) 339.4 V
13. A filtered full-wave rectifier voltage has a smaller ripple than does a half-wave rectifier voltage for the same load resistance and capacitor values because:
(A) There is a shorter time between peaks
(B) There is a longer time between peaks
(C) The larger the ripple, the better the filtering action
(D) None of the above
14. The peak inverse voltage (PIV) across a non conducting diode in a bridge rectifier equals approximately:
(A) Half the peak secondary voltage (B) Twice the peak secondary voltage
(C) The peak value of the secondary voltage (D) Four times the peak value of the secondary voltage
15. Shunting the ac component away from the load is the task of
(A) Transformer (B) Filter
(C) Regulator
(D)Rectifier
1. The device used for converting ac voltage into unidirectional current is called_____________
2. Efficiency of half wave rectifier=_____________________
3. PIV value of half wave rectifier is______________
4. The device which converts an ac voltage into pulsating dc voltage using both half cycles is called ______________
5. Ripple factor of full wave rectifier is _______________
6. Efficiency of full wave rectifier= ____________
7. Ripple factor of half wave rectifier is ___________
8. Form factor of full wave rectifier is ______________
9. PIV value of bridge rectifier is _______________
10. PIV value of full wave rectifier is _______________
11. The inductor filter should only used when load resistance is consistently ____________
12. The capacitor filter should only used when load resistance is ____________
1. In what decade was the first transistor created?
A) 1930s
B) 1940s
C) 1950s
D) 1960s
2. How many layers of material does a transistor have?
A) 1
B) 2
C) 3
D) 4
3. What is the ratio of the total width to that of the center layer for a transistor?
A) 1:15
B) 1:150
C) 15:1
D) 150:1
4. Which of the following is (are) the terminal(s) of a transistor?
A) Emitter
B) Base
C) Collector
D) All of the above
5. List the types of bipolar junction transistors.
A) p-p-n, n-p-n
B) p-n-p, n-p-n
C) n-p-p, p-p-n
D) n-n-p, p-n-p
6. Transistors are _____-terminal devices.
A) 2
B) 3
C) 4
D) 5
7. How many carriers participate in the injection process of a unipolar device?
A) 1
B) 2
C) 0
D) 3
8. Which component of the collector current IC is called the leakage current?
A) Majority
B) Independent
C) Minority
D) None of the above
9. For a properly biased p-n-p transistor, let IC = 10 mA and IE = 10.2 mA. What is the level of IB?
A) 0.2 A
B) 200 mA
C) 200 µA
D) 20.2 mA
10. Calculate minority current ICO if IC = 20.002 mA and IC majority = 20 mA.
A) 2 µA
B) 0.002 µA
C) 2 nA
D) 2 pA
11. Which of the following regions is (are) part of the output characteristics of a transistor?
A) Active
B) Cutoff
C) Saturation
D) All of the above
12. In which region are both the collector-base and base-emitter junctions forward-biased?
A) Active
B) Cut-off
C) Saturation
D) All of the above
13. How much is the base-to-emitter voltage of a transistor in the "on" state?
A) 0 V
B) 0.7 V
C) 0.7 mV
D) Undefined
14. In the active region, while the collector-base junction is _____-biased, the base-emitter is _____-biased.
A) forward, forward
B) forward, reverse
C) reverse, forward
D) reverse, reverse
15. What is βdc equal to?
A) IB / IE
B) IC / IE
C) IC / IB
D) None of the above
16. What are the ranges of the ac input and output resistance for a common-base configuration?
A) 10 Ω–100 Ω, 50 k Ω–1 MΩ
B) 50 kΩ –1 MΩ, 10 Ω –100 Ω
C) 10 Ω –100 kΩ, 50 Ω –1 kΩ
D) None of the above
17. For what kind of amplifications can the active region of the common-emitter configuration be used?
A) Voltage
B) Current
C) Power
D) All of the above
18. Use this table of collector characteristics to calculate βac at VCE = 15 V and IB = 30 µA.
A) 100
B) 106
C) 50
D) 400
19. Calculate βdc at VCE = 15 V and IB = 30 µA.
A) 100
B) 116
C) 50
D) 110
20. Which of the following configurations can a transistor set up?
A) Common-base
B) Common-emitter
C) Common-collector
D) All of the above
21. Determine the value of α when β = 100.
A) 1.01 B) 101 C) 0.99
D) Cannot be solved with the information provided
22. What is the most frequently encountered transistor configuration?
A) Common-base B) Common-collector C) Common-emitter D) Emitter-collector
23. βdc for this set of collector characteristics is within _____ percent of βac.
A) 2
B) 5
C) 7
D) 10
24. βdc = ________
A) IB / IE
B) IC / IE
C) IC / IB
D) None of the above
25. What is (are) the component(s) of most specification sheets provided by the manufacturer?
A) Maximum ratings
B) Thermal characteristics
C) Electrical characteristics
D) All of the above
26. What is (are) the component(s) of electrical characteristics on the specification sheets?
A) On
B) Off
C) Small-signal characteristics
D) All of the above
27. Most specification sheets are broken down into _____.
A) maximum ratings
B) thermal characteristics
C) electrical characteristics
D) All of the above
28. An example of a p-n-p silicon transistor is a 2N4123
A) True B) False
29. Which of the following equipment can check the condition of a transistor?
A) Current tracer
B) Digital display meter (DDM)
C) Ohmmeter (VOM)
D) All of the above
30. Which of the following can be obtained from the last scale factor of a curve tracer?
A) hFE
B) αdc
C) αac
D) βac
31. Calculate βac for IC = 15 mA and VCE = 5 V.
A) 200
B) 180
C) 220
D) None of the above
32. What range of resistor values would you get when checking a transistor for forward- and reverse-biased conditions by an ohmmeter?
A) 100 Ω to a few KΩ, exceeding 100 kΩ
B) Exceeding 100 KΩ, 100 Ω to a few kΩ
C) Exceeding 100 KΩ, exceeding 100 kΩ
D) 100 Ω to a few KΩ, 100 Ω to a few kΩ
33. What does a reading of a large or small resistance in forward- and reverse-biased conditions indicate when checking a transistor using an ohmmeter?
A) Faulty device
B) Good device
C) Bad ohmmeter
D) None of the above
34. A transistor can be checked using a (n) _____.
A) curve tracer B) digital meter
C) ohmmeter D) Any of the above
35. How many individual p-n-p silicon transistors can be housed in a 14-pin plastic dual-in-line package?
A) 4 B) 7 C) 10 D) 14
1. All amplifiers should have at least _____ terminals with _____ terminal(s) controlling the flow between _____ other terminal(s).
2. The outer layers of a transistor are _____ the sandwiched layer.
3. The doping of the sandwiched layer is _____ that of the outer layers.
4. The lower doping level _____ the conductivity and _____ the resistivity of the material.
5. The term bipolar reflects the fact that _____ and _____ participate in the injection process into the oppositely polarized material.
6. One p-n junction of a transistor is _____-biased and the other one is _____-biased in the active region.
7. The magnitude of the base current is typically on the order of _____ as compared to _____ for the emitter.
8. The base current is the _____ of the emitter and collector currents.
9. The _____ region is the region normally employed for linear (undistorted) amplifiers.
10. In the cutoff region the collector-base junction is _____-biased and the base-emitter junction is _____-biased for a transistor.
11. In the saturation region the collector-base junction is _____-biased and the base-emitter junction is _____-biased for a transistor.
12. For practical transistors the level of alpha typically extends from _____ to _____ with most approaching the higher end of the range.
13. Typical values of voltage amplification for the common-base configurations vary from _____ and the current gain is always _____ .
14. If a value of beta.gif is specified for a particular transistor configuration it will normally be used for _____ calculations.
15. The common-collector configuration has_____ input impedance and a _____ output impedance.
16. The active region of a transistor is bounded by the _____.
17. The "on" and "off" characteristics refer to _____ limits while the small-signal characteristics indicate the parameters of importance to _____ operation.
18. The step function (per step) of a curve tracer reveals the scale for _____.
19. The level of _____ is determined and displayed by advanced digital meters.
20. The level of _____ is determined and displayed by advanced digital meters if using diode-testing mode.
21. When checking a transistor by ohmmeter, a relatively _____ resistance is displayed for a forward-biased junction and _____ resistance for a reverse-biased junction.
22. An OL indication on an advanced digital meter indicates _____ while checking a transistor.
23. If the positive lead of an ohmmeter is connected to the base and the negative lead to the emitter, a low resistance reading would indicate a _____ transistor and a high resistance reading would indicate a _____ transistor.
24. The leads of a transistor are typically made of _____.
1) Junction Field Effect Transistors (JFET) contain how many diodes?
a) 4 b) 3 c) 2 d) 1
2) When an input delta of 2 V produces a transconductance of 1.5 mS, what is the drain current delta?
a) 666 mA b) 3 mA c) 0.75 mA d) 0.5 mA
3) A "U" shaped, opposite-polarity material built near a JFET-channel center is called the:
a) gate b) block c) drain d) heat sink
4) In the constant-current region, how will the IDS change in an n-channel JFET?
a) As VGS decreases ID decreases. b) As VGS increases ID increases.
c) As VGS decreases ID remains constant. d) As VGS increases ID remains constant.
5) IDSS can be defined as:
a) the minimum possible drain current
b) the maximum possible current with VGS held at –4 V.
c) the maximum possible current with VGS held at 0 V.
d) the maximum drain current with the source shorted.
6) What is the input impedance of a common-gate configured JFET?
a) very low b) Low c) high d) very high
7) JFET terminal "legs" are connections to the drain, the gate, and the:
a) channel b) substrate c) cathode d) source
8) Which JFET configuration would connect a high-resistance signal source to a low-resistance load?
a) Source follower b) common-source c) common-drain d) common-gate
9) How will electrons flow through a p-channel JFET?
a) from source to drain b) from source to gate c) from drain to gate d)from drain to source
10) Which are the majority charge carriers in P-channel JFET by enhancing the flow of current between two N-regions or gates?
a) Holes b). Electrons c) Both a and b d) None of the above
11) Which internally connected region is heavily doped with an impurity by forming double P-N junctions in JFET?
a) Source b) Drain c) Gate d) Channel
12) The passage of majority charge carriers from source to drain terminal takes place through the channel only after an application of
a) Drain to Source Voltage (VDS) b) Gate to Source Voltage (VGS)
c) Gate to Gate Voltage (VGG) d) Drain to Drain Voltage (VDD)
13) According to the symbolic representation of N and P channels , the gate arrow is always pointed towards ______.
a) p-type material b) n-type material
c) p-type in p-channel FET and n-type in n-channel FET d) All of the above
14) On the application of VDD to JFET, the biasing strategy of gate to channel at any point over the channel yields output equal to _______.
a) numerical sum of VDS and VGS b) numerical difference of VDS and VGS
c) numerical product of VDS and VGS d) numerical division of VDS and VGS
15) Which current is generated due to shorting of gate terminal to source with zero value of gate-to-source voltage?
a) Zero-source voltage drain current b) Zero-drain voltage gate current
c) Zero-source voltage gate current d) Zero-gate voltage drain current
16) JFET is considered as a voltage controlled device because ______.
a) gate current is controlled by drain voltage b) drain current is controlled by gate voltage
c) gate current is controlled by source voltage d) drain current is controlled by source voltage
17) Which type of static characteristics exhibit the relationship between drain current and gate-to-source voltage for several values of drain-to-source voltage?
a) Drain characteristics b) Transfer characteristics c). Both a and b d). None of the above
18) Which region of drain characteristic displays linearity with the direct variation in current corresponding to voltage especially for lesser values of drain-to-source voltage (VDS) by enabling the JFET to act as an ordinary resistor?
a) Breakdown Region b) Pinch-off Region c) Ohmic Region d). Saturation Region
19) Match the following FET behaviour with respective Drain Characteristic Regions:
1) Resistor A) Breakdown Region
2) Constant-Current Source B) Ohmic Region
3) Constant -Voltage Source C) Pinch-off Region
a) 1-A , 2-C , 3-B b) 1-C , 2-B , 3-A c) 1-A , 2-B , 3-C d) 1-B , 2-C , 3-A
20) Which kind of small signal JFET parameter is also a well-known form of 'Dynamic Drain Resistance' across the drain and source terminals especially when the operation of JFET is faciliated in pinch-off region?
a) AC Drain Resistance b) DC Drain Resistance
c) Ohmic Resistance d) Transconductance
1) To get a negative gate-source voltage in a self-biased JFET circuit, you must use a ________
2) One advantage of voltage-divider bias is that the dependency of drain current, ID, on the range of Q points is _________.
3) Changing ________ can control the voltage gain of a common-source amplifier.
4) A __________ change in VDS will produce a __________ change in ID.
5) A _______________ JFET amplifier provides a voltage gain of less than one.
6) The gate-to-source voltage VGS of a(n) ________ must be larger than the threshold VGS(Th) for the transistor to conduct.
7) _______is the network-input impedance for a JFET fixed-bias configuration.
8) The isolation between input and output circuits in the ac equivalent circuit is lost in a ________ configuration.
9) ______ is the amplification factor in FET transistor amplifiers.
10) The ________ does not support Shockley's equation.
11) The transconductance gm ________ as the Q-point moves from Vp to IDSS.
12) rd changes from one operation region to another with ________ values typically occurring at ________ levels of VGS (closer to zero).
13) The ________ is quite popular in digital circuits, especially in CMOS circuits that require very low power consumption.
14) ___________________ configuration(s) has (have) Zo RD.
15) The input and output signals are in phase in a ________ configuration.
16) gm has its maximum value for a JFET at ________.
17) _______ is the only parameter that is different between voltage-divider and fixed-bias configurations.
18) The ________ controls the ________ of an FET.
19) The ________ configuration has input impedance, which is other than RG.
20) The ________ configuration has the distinct disadvantage of requiring two dc voltage sources.