This is the Section 4 Module 2 of the compiled Electronics Coaching Materials taken from different sources including but not limited to Electronics books, past Board Exams Questions, Journals and other Electronics References. This particular Coaching Notes in Electronics Engineering has random Questions and Answers in random topics. Make sure to familiarize each questions to increase the chance of passing the ECE Board Exam.
Electronics Engineering Coaching: Section 4 Module 2
AC/DC CIRCUITS
1. A complex circuit simplified to an open circuit voltage and open circuit resistor
THEVENIN'S THEOREM
2. What theorem is used in solving electrical circuit swith several voltage sources?
SUPERPOSITION
3. Refer to current pulses that flow in the same direction
PULSATING DIRECT CURRENT
4. Relays are used to.
DECREASE THE CURRENT IN THE CIRCUIT
5. Damage to the electric component occurs at what minimum electrostatic potential.
35 VOLTS
6. Type of converter used to convert DC voltage to AC voltage
INVERTER
7. A process of converting an alternating current to a pulsating dc.
RECTIFICATION
8. In circuit, it is use to convert AC voltage to DC voltage
RECTIFIER
9. Vrms in an ac…
HOLDING VOLTAGE
10. A value at any instant time
INSTANTANEOUS VALUE
11. Voltage/current along at any instant of time
INSTANTANEOUS
12. Frequency is inversely proportional to . . . slope
SINE WAVE
13. What is the amplitude of two waves with equal amplitude and frequency but opposite in phase
ZERO ( THE SIGNAL WILL CANCEL EACH OTHER)
14. Represents a cycle of degree of phase
1/360
15. The angular frequency of a 60-Hz AC source
377 RAD/SEC
16. Two same frequencies 1/10 cycle apart has a phase difference of
36 DEGREES
17. Two AC signals with the same frequency but differs in phase by 1/10 of a cycle. What is the difference of two signals?
36 degrees
18. The length of time between a point in one cycle and the same point in the next cycle of an AC wave is the ___
PERIOD
19. When a capacitor is placed in an AC supply, the current ____ voltage by 90 degrees
LEADS
20. The absolute value of the impedance in a circuit increases _____
THE FLOW OF AC DECREASES
21. Relay that conducts only when current is supplied.
NORMALLY OPEN
22. When there is a reactance in the load where the transformer is connected
PERFECT IMPEDANCE MATCH CANNOT BE OBTAINED
POWER SUPPLY / GENERATORS and MOTORS
1. Efficiency of silicon solar cells _____
22%
2. Efficiency of a full wave rectifier
81.2%
3. Efficiency of a half wave rectifier
40.6%
4. In full-wave rectifier, the ripple is ________ than that of a half-wave rectifier.
TWICE
5. Combination of cells connected in series
BATTERY
6. A battery consists of_____________.
NUMBER OF CELLS
7. A lantern battery is most like to be found in __
A TWO WAY RADIO
8. A nickel-iron cell has a nominal voltage of 1.2V. It is also known as ___ cell.
EDISON
9. A modified version of the UPS which is used as back-up power supply
STAND-BY POWER SUPPLY
10. Where would you most likely find a lead-acid battery?
IN AN UNINTERRUPTABLE POWER SUPPLY
11. As a rule of thumb, Power rectifier ... back-to-front or front-to-back ratio is ____
10-to-1
12. As a rule of thumb, Signal diode ... back-to-front or front-to-back ratio is _____
300-to-1
13. A modified UPS wherein the power line itself serves as a back-up for the system
STANDBY POWER SUPPLY
14. In a Carbon zinc battery, zinc serves as
NEGATIVE CATHODE
15. What is the advantage of Alkaline cell over zinc-carbon cell
ALKALINE CELL WORKS WITH LOW TEMPERATURE
16. An advantage of alkaline cell over zinc-carbon cells
THE ALKALINE CELL CAN DELIVER USEFUL CURRENT AT LOWER TEMPERATURES
17. (mahabang intro…..tapos,)If you need low volume, low mass, and do not need regular maintenance, what type of battery should you use?
LITHIUM BATTERY
18. Typical output of silicon photovoltaic cell
0.6 VOLTS
19. Maximum theoretical efficiency of solar cell
22%
20. The electrical power that a solar panel can provide either in direct sunlight depends on all of the following factors except
AC VOLTAGE APPLIED DIRECT TO PANEL
21. A variable positive regulator.
317 (usually LM 317)
22. A fixed positive regulator
74XX
23. The most efficient regulator, used for high voltage and high current application
SWITCHING REGULATOR
24. Regulator that dissipates less power and less heat
SWITCHING REGULATOR
25. Linear regulator in which the load connected to the unregulated source must be kept constant
SHUNT REGULATOR
26. A regulator that dissipates less heat and less power
SWITCHING REGULATOR
27…frequency varies…
VOLTAGE CONTROLLED RECTIFIER
28. In a rectifier, to have a desired dc voltage output, ________ should be installed.
FILTER CAPACITOR
29. A current surge takes place when a power supply is first turned on because, ___
FILTER CAPACITOR MUST BE INITIALLY CHARGED
30. The part of a power supply immediately preceding the regulator is
FILTER
31. It is not a main component of an AC power supply.
RECTIFIER
32. A plate-type capacitor with two stator sections and a single rotor section common on both stators
BUTTERFLY CAPACITOR
33. If there is reactance in the load to which a transformer is connected, then _____
A PERFECT IMPEDANCE MATCH CANNOT BE OBTAINED
34. When reactance exists in the output of a ??? transformer,
THERE WILL ALWAYS BE AN IMPEDANCE MISMATCH
35. Maximum efficiency of half-wave rectifier
40.6 %
36. One revolution is equal to 200 steps. What is the angle movement?
1.8
37. Which is easily filtered by a power supply?
HIGH FREQUENCY PULSATING DC
38. Which motor is the best choice for handling heavy loads at short duration
COMMULATIVELY COMPOUNDED
39. In shunt wound with constant speed, as the current increases the _____
TERMINAL VOLTAGE INCREASES
40. The spin of a motor is 100% until the motor reach
LOW VALUE
41. Maintains the current in varying load better than series
SHUNT
42. Two primary parts of a rotating generator
PERMANENT OR TEMPORARY MAGNETS AND ARMATURE WINDINGS
43. Alternative to DC Motor as actuator.
PIEZO MOTOR OR ULTRASONIC MOTOR
44. Compared to straight cut spur gear, helical gear has_____________.
LESS BACKLASH
45. The current in secondary winding is greater than primary winding in step-up transformer. This statement is _______.
FALSE
46. A transducer which converts linear motion of the object mechanically connected to it to electrical signal
LINEAR VARIABLE DIFFERENTIAL TRANSFORMER (LVDT)
47. A shell method in transformer winding
PULSE MAXIMUM COUPLING
48. The electronic transfer of energy from one stage to another is called_______.
COUPLING
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