MCQOPTIONS
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MCQOPTIONS
This section includes 1475 Mcqs, each offering curated multiple-choice questions to sharpen your Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 751. |
The current induced by photoelectric effects is the ________ current of the transistor. |
| A. | collector |
| B. | base |
| C. | emitter |
| D. | None of the above |
| Answer» C. emitter | |
| 752. |
The switching time of an opto-isolator ________ with increased current, while for many devices it is exactly the reverse. |
| A. | increases |
| B. | decreases |
| C. | remains the same |
| D. | None of the above |
| Answer» C. remains the same | |
| 753. |
The ________ are the terminals of SCRs. |
| A. | anode and cathode |
| B. | anode, gate, and cathode |
| C. | base, anode, and cathode |
| D. | gate and anode |
| Answer» C. base, anode, and cathode | |
| 754. |
In general, the triggering (turn-on) anode gate current is ________ the required cathode gate current. |
| A. | larger than |
| B. | the same as |
| C. | smaller than |
| D. | None of the above |
| Answer» B. the same as | |
| 755. |
The four-layer devices with a control mechanism are commonly referred to as ________. |
| A. | thyristors |
| B. | transistors |
| C. | diodes |
| D. | None of the above |
| Answer» B. transistors | |
| 756. |
________ is(are) example(s) of applications of phototransistors. |
| A. | Punch-card readers |
| B. | Lighting control (for example, on highways) |
| C. | Level indication |
| D. | All of the above |
| Answer» E. | |
| 757. |
________ in light intensity corresponds with ________ in collector current. |
| A. | An increase, an increase |
| B. | An increase, a decrease |
| C. | A decrease, an increase |
| D. | None of the above |
| Answer» B. An increase, a decrease | |
| 758. |
Which of the following devices does not have a cathode terminal? |
| A. | SCR |
| B. | SCS |
| C. | Triac |
| D. | Shockley diode |
| Answer» D. Shockley diode | |
| 759. |
________ is (are) the element(s) of a unijunction transistor's equivalent circuit. |
| A. | One fixed resistor |
| B. | A variable resistor |
| C. | A diode |
| D. | All of the above |
| Answer» E. | |
| 760. |
To turn on an SCS device, a ________ pulse must be applied to the anode gate terminal; to turn off the device, a ________ pulse is required. |
| A. | positive, positive |
| B. | negative, positive |
| C. | positive, negative |
| D. | negative, negative |
| Answer» C. positive, negative | |
| 761. |
In a half-wave variable-resistance phase control operation, the control cannot be extended past a ________ phase displacement. |
| A. | 45 |
| B. | 90 |
| C. | 135 |
| D. | 180 |
| Answer» C. 135 | |
| 762. |
Today, the SCR is more widely used than the TRIAC. |
| A. | True |
| B. | False |
| Answer» C. | |
| 763. |
Which of the following devices is unquestionably of the greatest interest today? |
| A. | SCR |
| B. | GTO |
| C. | LASCR |
| D. | SCS |
| Answer» B. GTO | |
| 764. |
Which of the following devices has a negative-resistance region in its characteristics curve? |
| A. | SCR |
| B. | SCS |
| C. | Unijunction transistor |
| D. | Phototransistor |
| Answer» D. Phototransistor | |
| 765. |
One of the key characteristics of an instrumentation amplifier is high input impedance. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 766. |
Instrumentation amplifiers are commonly used in environments with high common-mode noise. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 767. |
A constant-current source delivers a load current that remains constant only when the load resistance remains constant. |
| A. | True |
| B. | False |
| Answer» C. | |
| 768. |
There is a small amount of current across the barrier of a reverse-biased diode. This current is called |
| A. | forward-bias current. |
| B. | reverse breakdown current. |
| C. | conventional current. |
| D. | reverse leakage current. |
| Answer» E. | |
| 769. |
As the forward current through a silicon diode increases, the voltage across the diode |
| A. | increases to a 0.7 V maximum. |
| B. | decreases. |
| C. | is relatively constant. |
| D. | decreases and then increases. |
| Answer» D. decreases and then increases. | |
| 770. |
A reverse-biased diode has the ________ connected to the positive side of the source, and the ________ connected to the negative side of the source. |
| A. | cathode, anode |
| B. | cathode, base |
| C. | base, anode |
| D. | anode, cathode |
| Answer» B. cathode, base | |
| 771. |
What types of impurity atoms are added to increase the number of conduction-band electrons in intrinsic silicon? |
| A. | bivalent |
| B. | octavalent |
| C. | pentavalent |
| D. | trivalent |
| E. | none of the above |
| Answer» D. trivalent | |
| 772. |
What factor(s) do(es) the barrier potential of a pn junction depend on? |
| A. | type of semiconductive material |
| B. | the amount of doping |
| C. | the temperature |
| D. | all of the above |
| E. | type of semiconductive material and the amount of doping but not the temperature |
| Answer» E. type of semiconductive material and the amount of doping but not the temperature | |
| 773. |
An atom is made up of |
| A. | protons. |
| B. | neutrons. |
| C. | electrons. |
| D. | all of the above |
| Answer» E. | |
| 774. |
The peak and valley currents of the PUT are typically ________ those of a similarly rated UJT. |
| A. | lower than |
| B. | the same as |
| C. | higher than |
| D. | None of the above |
| Answer» B. the same as | |
| 775. |
The ________ the anode gate current, the ________ the required anode-to-cathode voltage to turn the SCS device on. |
| A. | higher, higher |
| B. | lower, lower |
| C. | higher, lower |
| D. | None of the above |
| Answer» D. None of the above | |
| 776. |
SCRs have been designed to control powers as high as ________, with individual ratings as high as ________ at ________. |
| A. | 1800 MW, 10 A, 2000 V |
| B. | 1800 MW, 2000 A, 10 V |
| C. | 10 MW, 2000 A, 1800 V |
| D. | 2000 MW, 10 A, 1800 V |
| Answer» D. 2000 MW, 10 A, 1800 V | |
| 777. |
The two-layer semiconductor diode has led to ________layer devices. |
| A. | three- |
| B. | four- |
| C. | five- |
| D. | All of the above |
| Answer» E. | |
| 778. |
The minimum operating voltage of the UJT is typically ________ that of a similarly rated PUT. |
| A. | lower than |
| B. | the same as |
| C. | higher than |
| D. | None of the above |
| Answer» D. None of the above | |
| 779. |
What occurs when a conduction-band electron loses energy and falls back into a hole in the valence band? |
| A. | doping |
| B. | recombination |
| C. | generation |
| Answer» C. generation | |
| 780. |
Which of the following devices has nearly the same turn-on time as turn-off time? |
| A. | SCR |
| B. | GTO |
| C. | SCS |
| D. | LASCR |
| Answer» C. SCS | |
| 781. |
This symbol is an example of a(n) ________. |
| A. | SCR |
| B. | SCS |
| C. | GTO |
| D. | DIAC |
| Answer» B. SCS | |
| 782. |
Which one of the SCR terminals fires the SCR? |
| A. | Anode |
| B. | Cathode |
| C. | Gate |
| D. | All of the above |
| Answer» D. All of the above | |
| 783. |
Which of the following devices has the smallest turn-off time? |
| A. | SCR |
| B. | GTO |
| C. | SCS |
| D. | LASCR |
| Answer» C. SCS | |
| 784. |
This symbol is an example of a(n)________. |
| A. | SCR |
| B. | SCS |
| C. | GTO |
| D. | DIAC |
| Answer» C. GTO | |
| 785. |
Which of the following transistors is an SCR composed of? |
| A. | <i>npn, pnp</i> |
| B. | <i>npn, npn</i> |
| C. | <i>pnp, pnp</i> |
| D. | None of the above |
| Answer» B. <i>npn, npn</i> | |
| 786. |
A thyristor is a ________-layer semiconductor material device. |
| A. | 2 |
| B. | 3 |
| C. | 4 |
| D. | 5 |
| Answer» D. 5 | |
| 787. |
How many layers of semiconductor materials does a silicon-controlled rectifier (SCR) have? |
| A. | 2 |
| B. | 3 |
| C. | 4 |
| D. | 5 |
| Answer» D. 5 | |
| 788. |
This symbol is an example of a(n) ________. |
| A. | SCR |
| B. | SCS |
| C. | GTO |
| D. | DIAC |
| Answer» E. | |
| 789. |
How many terminals does a silicon-controlled switch (SCS) device have? |
| A. | 2 |
| B. | 3 |
| C. | 4 |
| D. | 5 |
| Answer» D. 5 | |
| 790. |
What is the typical value of the triggering anode gate for SCS devices? |
| A. | 1.5 mA |
| B. | 150 A |
| C. | 15 A |
| D. | 1 A |
| Answer» B. 150 A | |
| 791. |
Which of the following is (are) the advantages of the SCS over a corresponding SCR? |
| A. | Reduced turn-off time |
| B. | Increased control and triggering sensitivity |
| C. | More predictable firing situation |
| D. | All of the above |
| Answer» E. | |
| 792. |
This is an example of a high-isolation ________ gate. |
| A. | OR |
| B. | NOT |
| C. | AND |
| D. | NAND |
| Answer» D. NAND | |
| 793. |
Which of the following devices has (have) four layers of semiconductor materials? |
| A. | Silicon-controlled switch (SCS) |
| B. | Gate turn-off switch (GTO) |
| C. | Light-activated silicon-controlled rectifier (LASCR) |
| D. | All of the above |
| Answer» E. | |
| 794. |
What is the maximum current (rms) rating for commercially available LASCRs today? |
| A. | 3 A |
| B. | 15 A |
| C. | 20 A |
| D. | 25 A |
| Answer» B. 15 A | |
| 795. |
Which of the following areas is (are) applications of an SCS? |
| A. | Counters |
| B. | Pulse generators |
| C. | Voltage sensors |
| D. | All of the above |
| Answer» E. | |
| 796. |
For an SCS, a ________ pulse at the anode gate turns the device on, while a ________ pulse will turn it off. |
| A. | negative, positive |
| B. | positive, negative |
| Answer» B. positive, negative | |
| 797. |
An advantage of the SCR over the SCS is the reduced turn-off time. |
| A. | True |
| B. | False |
| Answer» C. | |
| 798. |
This symbol is an example of a(n) ________. |
| A. | SCR |
| B. | SCS |
| C. | GTO |
| D. | diac |
| Answer» D. diac | |
| 799. |
Calculate the output voltage. |
| A. | 6.00 mV |
| B. | 6.0 mV |
| C. | 6.12 mV |
| D. | 6.12 mV |
| Answer» D. 6.12 mV | |
| 800. |
An example of an instrumentation circuit is a(n) ________. |
| A. | dc voltmeter |
| B. | display driver |
| C. | ac voltmeter |
| D. | All of the above |
| Answer» E. | |