General - Ch. 12 - Fundamentals of Electricity and electronics
3. 994.6 watts due to friction and heat loss, motors are not 100% efficient. therefore, it will take more than 746 watts to maintain a 1 horsepower output. calculate the watts needed by dividing 746 by 75%, which equals 994.6 watts the voltage is irrelevant in this example ch. 12 pg. 22
12-14. a 1-horsepower, 24 volt DC electric motor that is 80% efficient requires 932.5 watts. How much power will a 1-horsepower, 12-volt DC electric motor that is 75% efficient require? 1. 832.5 watts 2. 900.5 watts 3. 994.6 watts
3. 2 lights requiring 3 amperes each in a 24 volt parallel system 12 volt motor x 8 amps = 96 watts 4 lamps x 30 watts = 120 watts 2 (3 amps x 24 volts) = 144 watts ch. 12 pg. 22
12-15. which requires the most electrical power during operation? note: 1 horsepower = 746 watts 1. a 12-volt motor requiring 8 amperes 2. four 30-watt lamps in a 12-volt parallel circuit 3. two lights requiring 3 amperes each in a 24-volt parallel system
2. 198.93 watts 1. 4 x 30 = 120 2. (746 x .2) / .75 = 198.93 3. 2 x (24 volts x 3 amps) = 144
12-16. Which requires the most electrical power? Note: 1 horsepower = 746 watts 1. four 30 watt lamps arranged in a 12 volt parallel circuit 2. a 1/5 horsepower, 24 volt motor which is 75% efficient 3. a 24 volt anti collision light circuit consisting of 2 light assemblies, which require 3 amperes each during operation
2. #3 symbol 3 is a variable resistor symbol 2 is a relay symbol 4 is a circuit breaker ch. 12 pg. 27-28
12-17. refer to the figure. Which symbol in figure 12-2 represents a variable resistor? 1. #2 2. #3 3. #4
2. #3 symbol 3 is a potentiometer or variable resistor symbol 2 is a relay symbol 4 is a circuit breaker ch. 12 pg. 27-28
12-18 refer to the figure. Which of the components is a potentiometer in the figure? 1. #2 2. #3 3. #4
1. the motor will reset itself a thermal protector switch contains a bimetallic strip that bands when it is heated, which opens the circuit. once the temperature reduces, the strip bends back, closing the circuit again, allowing further operation. ch. 12 pg. 30
12-19. If a thermal protector switch activates to prevent overheating damage to an electric motor, once the motor has cooled; ____________________ 1. the motor will reset by itself 2. the circuit can be reset from the flight deck 3. the circuit protector is replaced by a maintenance crew
2. iron permeability is the measure of the ease with which a magnetic flux can pass through a material. of the 3 options, iron has the highest permeability ch. 12 pg. 11
12-2. through which material will magnetic lines of force pass the most readily? 1. copper 2. iron 3. aluminum
2. 3 Volts with the series-parallel set up in this, at any given point, only 2 batteries are in series at a time, while a set is in parallel as well. so 1.5v + 1.5v = 3 volts, the set in parallel would give off an equal 3v as well. ch. 12 pg. 36
12-20. refer to the figure. what is the measured voltage of the series-parallel circuit between terminal A and B? 1. 1.5 volts 2. 3 volts 3. 4.5 volts
2. 26 ohms using ohms law V= I x R & the power law P = V x I 30w / 28v = 1.07a 28v / 1.07a = 26.16 ohms ch. 12 pg. 38
12-21. what is the operating resistance of a 30-watt light bulb designed for a 28-volt system? 1. 1.07 ohms 2. 26 ohms 3. 0.93 ohms
2. at least 35 milliwatts use ohms law 14 ohms x .05 amps = .7 volts .7 volts x .05 amps = .035 watts .035 watts x 1000 = 35 milliwatts ch. 12 pg. 39
12-22. a 14 ohm resistor is to be installed in a series circuit carrying .05 ampere. how much power will the resistor be required to dissipate? 1. at least .70 milliwatts 2. at least 35 milliwatts 3. less than .035 watts
3. 24 volts in a parallel circuit, the voltage remains the same across each resistor ch. 12 pg. 40
12-23. refer to the figure. find the voltage across the 8 ohm resistor. 1. 8 volts 2. 20.4 volts 3. 24 volts
3. 24 volts in a parallel circuit, the voltage across any branch is equal to the voltage across all other branches ch. 12 pg. 40
12-24. in a parallel circuit with four 6-ohm resistors across a 24 volt battery, what is the total voltage across resistor-three (VR3) in the circuit? 1. 6 volts 2. 18 volts 3. 24 volts
2. the total current is equal to the sum of the currents through the individual branches of the circuit ch. 12 pg. 41
12-25. which statement is correct when made in reference to a parallel circuit? 1. the current is equal in all portions of the circuit 2. the total current is equal to the sum of the currents through the individual branches of the circuit 3. the current in amperes can be found by dividing EMF in volts by the sum of the resistors in ohms
3. 25.23 amps to find total resistance: 1/[(1/R1) + (1/R2) + (1/R3) + (1/R4) + (1/R5) = 1/ [1/6 + 1/6 + 1/6 + 1/5 + 1/5] = 1/[ .167 + .167 + .167 + .2 + .2] = 1/.901 1/.901 = 1.109 or if you round up, 1.11 ohms total resistance now I = E/R I = 28 volts / 1.11 ohms I = 25.23 amps ch. 12 pg. 41
12-26. how many amperes will a 28 volt generator be required to supply to a circuit containing 5 lamps in parallel, 3 of which have a resistance of 6 ohms each and 2 of which have a resistance of 5 ohms each? 1. 1.11 amps 2. 15.30 amps 3. 25.23 amps
3. 24 volts no calculations needed. the sum of all the voltage drops in a circuit equal the sum of the voltage sources in the circuit ch. 12 pg. 42
12-27. A 24-volt source is required to furnish 48 watts to a parallel circuit consisting of 4 resistors of equal value. What is the voltage drop across each resistor? 1. 3 volts 2. 12 volts 3. 24 volts
1. equal to the voltage across the 20 watt light in a parallel circuit, the voltage is constant across each path, while the current varies. the voltage across the 10 watt light will be equal to the voltage across the 20 watt light ch. 12 pg. 41
12-28. A cabin entry light of 10 watts and a dome light of 20 watts are connected in parallel to a 30 volt source. if the voltage across the 10 watt light is measured, it will be: 1. equal to the voltage across the 20 watt light 2. half the voltage across the 20 watt light 3. one third of the input voltage
2. 3 ohms with R5 disconnected, it registers the remaining resistors. R3 and R4 are in series, so their total is added R34 = 12 ohms. R1 and R2 are in parallel with R3 and R4. to calculate, do the following 1/[(1/R1) + (1/R2) + (1/R34) = 1/[(1/12) + (1/6) + (1/12)] = 1/(.08 + .17 + .08) = 1/.33 = 3.03 ohms ch. 12 pg. 41
12-29. Refer to the figure. if resistor R5 is disconnected at the junction of R4 and R3 as shown, what will the ohmmeter read? 1. 2.76 ohms 2. 3 ohms 3. 12 ohms
1. volts a volt is the basic unit of electrical potential or electromotive force ch. 12 pg. 16
12-3. The potential difference between 2 conductors which are insulated from each other is measured in: 1. volts 2. amps 3. coulombs
1. infinite resistance there is no possible way for electricity to connect both ends of the ohm meter due to the break, so the resistance is infinite ch. 12 pg. 41
12-30. referring to figure 12-6, if resistor R3 is disconnected at the break point between it and terminal D, what will the ohmmeter read? 1. infinite resistance 2. 10 ohms 3. 20 ohms
2. infinite resistance there is no possible way for electricity to connect both ends of the ohm meter due to the break, so the resistance is infinite ch. 12 pg. 41
12-31. refer to the figure. with an ohmmeter connected into the circuit in figure 12-7, what will the ohmmeter read?
3. 21.2 ohms 1. solves for the parallel branches R45 = 1/(1/R4 + 1/R5) = 1/(1/12 + 1/6) = 1/.083 + .167 = 1/.25 = 4 then determine the resistance in the series R2 and R4, 5: R245 = R45 + R2 = 4 + 12 = 16 Solve for the next parallel branches: R2345 = 1/(1/R245 + 1/R3) = 1/(1/16 + 1/4) = 1/.0625 + .25 = 1/.3125 = 3.2 finally solve the last remaining series to determine the total resistance in this circuit: Rt = R2345 + R1 = 3.2 + 18 = 21.2 ohms ch. 12 pg. 41
12-32. find the total resistance of the circuit in the figure. 1. 22 ohms 2. 18.5 ohms 3. 21.2 ohms
1. 36 ohms 192/48v = 4a 48/4a = 12 ohm 1/12 = 1/.08333 1/12 / 3 = 1/.027777 1/.027777 = 36 (1/x)function on calculator ch. 12 pg. 22, 37, 41
12-33. a 48 volt source is required to furnish 192 watts to a parallel circuit consisting of three resistors of equal value. what is the value of each resistor? 1. 36 ohms 2. 4 ohms 3. 12 ohms
1. total resistance will be smaller than the smallest resistor ch. 12 pg. 40-41
12-34. Which is correct concerning a parallel circuit? 1. total resistance will be smaller than the smallest resistor 2. total resistance will decrease when one of the total resistances is removed 3. total voltage drop is the same as the total resistance
1. 10 volts for series circuits, current is the same throughout, but voltage drop varies with each resistor. first determine total resistance (10 ohm + 20 ohm = 30 ohm) next determine the current using ohms law I = V/R I = 30/30 = 1 A 1A x 10 ohms = 10V ch. 12 pg. 41, 43
12-35. A circuit has an applied voltage of 30 volts and a load consisting of a 10 ohm resistor in series with a 20 ohm resistor. what is the voltage drop across the 10 ohm resistor? 1. 10 volts 2. 20 volts 3. 30 volts
3. 1.4 amperes I = E/R I1 = 12V / 30 ohms = .4 amps I2 = 12V / 60 ohms = .2 amps I3 = 12V/ 15 ohms = .8A add the currents from each branch for a total of 1.4 amps (.4 + .2 + .8 = 1.4A) ch. 12 pg. 43
12-36. refer to the figure. determine the total current flow in the circuit 1. 0.2 Amperes 2. 0.8 amperes 3. 1.4 amperes
2. if one of 3 bulbs in a parallel lighting circuit is removed, the total resistance of the circuit will increase ch. 12 pg. 43
12-37. Which is correct in reference to electrical resistance? 1. two electrical devices will have the same combined resistance either connected in series or connected in parallel? 2. if one of 3 bulbs in a parallel lighting circuit is removed, the total resistance of the circuit will increase 3. a device that has a high resistance will use more power than one with a low resistance with the same applied voltage
3. 0.93 amps in a series circuit, current is always the same fine total resistance (3 + 5 + 22 = 30) use ohms law - 28V / 30 ohms = 0.93A ch. 12 pg 42
12-38. If three resistors of 3 ohms, 5 ohms, and 22 ohms are connected in series in a 28 volt circuit, how much current will flow through the 3 ohm resistor? 1. 9.3 amps 2. 1.05 amps 3. 0.93 amps
3. inductive reactance - the opposition to the flow of current ch. 12 pg. 44
12-39. the opposition offered by a coil to the flow of alternating current is called (disregard resistance) 1. impedance 2. reluctance 3. inductive reactance
3. milliampere ch. 12 pg. 17
12-4. Which term means .001 ampere? 1. microampere 2. kiloampere 3. millampere
2. smooth out slight pulsations in current/voltage the function of capacitors is to smooth out DC pulsations ch. 12 pg. 76
12-40. Capacitors are sometimes used in DC circuits to: 1. counteract inductive reactance at specific locations 2. smooth out slight pulsations in current/voltage 3. assist in stepping voltage and current up and/or down
3. at least 50% greater than the highest applied voltage ch. 12 pg. 52
12-41. The working voltage of a capacitor in an AC circuit should be: 1. equal to the highest applied voltage 2. at least 20% greater than the highest applied voltage 3. at least 50% greater than the highest applied voltage
3. The amount of electricity a capacitor can store is directly proportional to the plate area and inversely proportional to the distance between the plates ch. 12 pg. 52
12-42. The amount of electricity a capacitor can store is directly proportional to the: 1. distance between the plates and inversely proportional to the plate area 2. plate area and is not affected by the distance between the plates 3. plate area and inversely proportional to the distance between the plates
3. 3. equal to the sum of all the capacitances we can derive from the formula that capacitors in a parallel circuit are equal to teh sum of all the capacitances ch. 12 pg. 55
12-43. When different rated capacitors are connected in parallel in a circuit, the total capacitance is: Note: CT = C1 + C2 + C3...) 1. less than the capacitance of the lowest rated capacitor 2. equal to the capacitance of the highest rated capacitor 3. equal to the sum of all the capacitances
1. .4 microfarad CT = .25 microfarad + .03 + .12 = .4 microfarad ch. 12 pg. 55
12-44. What is the total capacitance of a circuit containing three capacitors with capacitances of .25 microfarad, .03 microfarad, and .12 microfarad, respectively? note: CT = C1 + C2 + C3....) 1. .4 microfarad 2. .04 picofarad 3. .04 microfarad
1. is called induction ch. 12 pg. 57
12-45. Transfer of electrical energy from one circuit to another without the aid of electrical connections: 1. is called induction 2. is called capacitance 3. is practical for use only with low voltages/amperages
3. equal to the sum of the individual inductances we can derive this answer from the equation provided. in a series circuit, total inductance (LT) is equal to the sum of the individual inductances ch. 12 pg. 59
12-46. When inductors are connected in series in a circuit, the total inductance is (where magnetic fields of each inductor do not affect the other) note: LT = L1 + L2 + L3 1. less than the inductors of the lowest rated inductor 2. equal to the inductance of the highest rated inductor 3. equal to the sum of the individual inductances
1. less than the inductance of the lowest rated inductor. this equation is identical to finding resistance totals in a parallel circuit. the same rule applies 1 LT =. ------------------------ 1/L1 + 1/L2 + 1/L3..... ch. 12 pg. 60
12-47. Referring to the figure, when more than two inductors of different inductances are connected in parallel in a circuit, the total inductance is: 1. less than the inductance of the lowest rated inductor 2. equal to the inductance of the highest rated inductor 3. equal to the sum of the individual inductances
1. inductance and frequency the inductive reactance of a component is directly proportional to the inductance of the component and the applied frequency to the circuit ch. 12 pg. 60
12-48. An increase in which of the following factors will cause an increase in the inductive reactance of a circuits: 1. inductance and frequency 2. resistance and voltage 3. resistance and capacitive reactance
3. impedance impedance is defined as the combined effects of resistance, inductive reactance, and capacitive reactance. together, these effects make up the total opposition to current flow in an AC circuit ch. 12 pg. 61
12-49. The term that describes the combined resistive forces in an AC circuit it: 1. resistance 2. reactance 3. impedance
1. amperes = charge / time the unit of electrical current is ampere answer a: I = Q / t I = current Q = charge in coulombs t = time ch. 12 pg. 17
12-5. Which is the correct formula that defines Current? 1. amperes = charge / time 2. volts = joules / charge 3. power = volts / time
3. 10 ohms 1. (XL - XC)² = (10 - 4)² = 6² = 36 36 > R² = 8² = 64 64 > 64 + 36 = 100 100 > square root of 100 = 10 10 ohms ch. 12 pg. 63
12-50. What is the impedance of an AC circuit consisting of an inductor with a reactance of 10 ohms, a capacitor with a reactance of 4 ohms, and a resistor with a resistance of 8 ohms? Z = √R²+(XL - XC)² Z= impedance / R = resistance / XL = inductive reactance / XC = capacitive reactance 1. 2.5 ohms 2. 5.29 ohms 3. 10 ohms
1. inductance when an alternating voltage is applied to (across) one coil, the varying magnetic field set up around that coil creates an alternating voltage in the other coil by mutual induction ch. 12 pg. 66
12-51. The basis for transformer operation in the use of alternating current is mutual 1. inductance 2. capacitance 3. reactance
3. less than apparent power when there is capacitance or inductance in the circuit, the current and voltage are not exactly in phase and the true power is less than the apparent power ch. 12 pg. 66
12-52. When calculating power in a reactive or inductive AC circuit, the true power is: 1. more than the apparent power 2. less than the apparent power in a reactive circuit and more than the apparent power in an inductive circuit 3. less than the apparent power
1. the current is stepped down by a 1 to 4 ratio if a transformer steps up the voltage, it will step down the current by the same ratio in this, with voltage stepping up 1:4 the current will step down 4:1 ch. 12 pg. 66
12-53. What happens to the current in a voltage step-up transformer with a ratio of 1 to 4? 1. the current is stepped down by a 1 to 4 ratio 2. the current is stepped up by a 1 to 4 ratio 3. the current does not change
3. 2 of them are installed correctly from left to right, the first ammeter is incorrect, since it is parallel to the circuit, which makes the second ammeter installed correctly from left to right, the first voltmeter has its polarity reversed the way its installed. its also installed in series in the circuit the second voltmeter is installed in parallel to the circuit, with the correct polarity, it is installed correctly going from left to right, the second ammeter and second voltmeter are installed correctly ch. 12 pg. 71-72
12-54. Refer to the figure. how many instruments (voltmeters and ammeters) are installed correctly? 1. all are installed correct 2. 1 is installed correctly 3. 2 are installed correctly
c. permit the battery voltage to appear on the voltmeter voltmeters should be connected parallel in a circuit, which it is. in this case, since the difference of voltage is the entire value of the battery due to the break, the battery voltage will appear on the voltmeter ch. 12 pg. 73
12-55. Troubleshooting an open circuit with a voltmeter as shown in the circuit in figure 12-11 below will: 1. permit current to illuminate the lamp 2. create a low resistance path and the current flow will be greater than normal 3. permit the battery voltage to appear on the voltmeter
3. in parallel with a unit also ensure the polarity of the connection is correct ch. 12 pg. 72
12-56. What is the correct way to connect a test voltmeter in a circuit? 1. in series with a unit 2. between source voltage and the load 3. in parallel with a unit
3. #19 if an open should occur in wire 19, the red indicator light will not turn on. wire 19 supplies power to the red indicator light via the up limit switch and wire 8. wire 7 supplies power to wire 18 for the red indicator light push to test circuit and wire 17 for the green indicator light push to test circuit ch. 12 pg. 89
12-57. refer to the figure. with the landing gear retracted, the red indicator light will not come on if an open occurs in wire: 1. #7 2. #17 3. #19
1. wire #7 is used to complete the push to test circuit wire 7 supplies power to both the red and green indicator lights push to test circuits. when the push to test button is pressed, the circuit is closed to ground. push to test buttons verify the bulb is working ch. 12 pg. 89
12-58. Refer to the figure. Wire #7 is used to: 1. complete the push to test circuit 2. open the UP indicator light circuit when the landing gear is retracted 3. close the UP indicator light circuit when the landing gear is retracted
1. #6 if there is an open in wire 6, the green light will not come on when the landing gear is down. however, if there is an open in wire 5, 4, or 3, the light would not come on either. in the real world, additional troubleshooting would need to be completed to locate the wire with the open condition along this circuit ch. 12 pg. 89
12-59. Refer to the figure. When the landing gear is down, the green light will not come on if an open condition occurs in which wire? 1. #6 2. #7 3. #17
1. 14.6 amps 1 hp = 746 watts 1/2 hp = 373 watts 373 / .85 = 438.82 438.82 watts / 30 volts = 14.62 amps ch. 12 pg. 22
12-6. how much current does a 30 volt, 1/2 horsepower motor that is 85% efficient draw from the bus? note: 1 horsepower = 746 watts 1. 14.6 amps 2. 12.4 amps 3. 14.1 amps
2. prevent sediment buildup from contacting the plates and causing a short circuit ch. 12 pg. 90
12-60. the purpose of proivding a space underneath the plates in a lead acid battery cell container is to: 1. ensure the electrolyte quantity ratio to the number of plates and plate area is adequate 2. prevent sediment buildup from contacting the plates and causing a short circuit 3. allow for convection flow of the electrolyte to provide cooling of the plate
3. apply sodium bicarbonate solution to the affected area followed by a water rinse ch. 12 pg. 93
12-61. if electrolyte from a lead acid battery is spilled in the battery compartment, which procedure should be followed? 1. apply boric acid solution to the affected area followed by a water rinse 2. rinse the affected area thoroughly with clean water 3. apply sodium bicarbonate solution to the affected area followed by a water rinse
1. the hydrometer reading does not require a temperature correction if the electrolyte temperature is 80 degrees F no correction is necessary when the temperature is between 70 degrees F to 90 degrees F. since the variation is not great enough to consider, when temperatures are greater than 90 F, or less than 70 F, it is necessary to apply a correction factor ch. 12 pg. 93
12-62. Which statement regarding the hydrometer reading of a lead-acid storage battery electrolyte is true? 1. the hydrometer reading does not require a temperature correction if the electrolyte temperature is 80 degrees F 2. a specific gravity correction should be subtracted from the hydrometer reading if the electrolyte temperature is above 20 degrees F 3. the hydrometer reading will give a true indication of the capacity of the battery regardless of the electrolyte temperature
2. the state of charge of the battery ch. 12 pg. 93
12-63. what determines the amount of current which will flow through a battery while it is being charged by a constant voltage source 1. the total plate ara of the battery 2. the state of charge of the battery 3. the ampere-hour capacity of the batery
1. 0.52 ohms to determine internal resistance, subtract the closed circuit voltage from the no load voltage and then divide by the closed circuit current no load voltage = 12 cells x 2.1 volts = 25.2 volts closed circuit voltage = 10 amps x 2 ohms = 20 volts closed circuit current = 10 amps (25.2 volts - 20 volts) / 10 amps = .52 ohms ch. 12 pg. 93
12-64. a lead acid battery with 12 cells connected in series (no load voltage = 2.1 volts per cell) furnishes 10 amperes to a load of 2 ohms resistance. the internal resistance of the battry in this instance is: 1. 0.52 ohm 2. 2.52 ohm 3. 5.0 ohm
3. batteries of the same voltage and same ampere-hour capacity must be connected in series with each other across the charger, and charged using the constant current method ch. 12 pg. 94
12-65. Which of the following statements is/are generally true regarding the charging of several aircraft batteries together? 1. batteries of different voltages (but similar capacities) can be connected in series with each other across the charger, and charged using the constant current method 2. batteries of different ampere-hour capacity and same voltage can be connected in parallel with each other across the charger, and charged using the constant voltage method 3. batteries of the same voltage and same ampere-hour capacity must be connected in series with each other across the charger, and charged using the constant current method
1. toward the end of the charging cycle the cells of a nicad battery emit gas toward the end of the charging cycle. this can also occur. if the cells are over charged ch. 12 pg. 94
12-66. when a charging current is applied to a nickel-cadmium battery, the cells emit gas: 1. toward the end of the charging cycle 2. throughout the charging cycle 3. if the electrolyte level is too high
3. carbon generally in lithium ion, the negative electrode is made of carbon, while the positive electrode is a metal oxide, and the electrolyte is lithium salt within a solvent ch. 12 pg. 95
12-67. in a lithium ion battery, what is the negative electrode generally made from? 1. lithium 2. a metal oxide 3. carbon
1. in a fully charged condition on recharge, the level of the electrolyte rises, and at full charge, the electrolyte will be at its highest level ch. 12 pg. 95
12-68. the electrolyte of a nickel-cadmium battery is highest when the battery is: 1. in a fully charged condition 2. in a discharged condition 3. under a no-load condition
3. depends upon its temperature and the method used for charging ch. 12 pg. 95
12-69. The end-of-charge voltage of a 19-cell nickel-cadmium battery, measured while still on charge 1. must be 1.2 to 1.3 volts per cell under normal operating temperature 2. must be 1.4 volts per cell averaged across the number of cells 3. depends upon its temperature and the method used for charging
3. the amperage in the circuit ohms law = E = I(R) E = voltage I = current R = resistance if resistance is known, then you would need the amperage value to determine voltage drop ch. 12 pg 18
12-7. The voltage drop in a circuit of known resistance is dependent on: 1. the voltage of the circuit 2. the resistance of the conductor and does not change with voltage or amperage 3. the amperage of the circuit
3. electrolyte becomes absorbed into the plate this drops the electrolyte level in the cells ch. 12 pg. 95
12-70. nickel-cadmium batteries, which are stored for a long period of time, will show a low liquid level because: 1. of the decrease in the specific gravity of the electrolyte 2. electrolyte evaporates through the vents 3. electrolyte becomes absorbed into the plate
2. by a measured discharge unlike lead acid batteries, nicad batteries cannot use a hydrometer to test for the state of charge. the only way to determine the state of charge for nicad batteries is to fully discharge the battery, then recharge and measure the amount of charge put back into the battery ch. 12 pg. 95
12-71. how can the state-of-charge of a nickel-cadmium battery be determined? 1. by measuring the specific gravity of the electrolyte 2. by a measured discharge 3. by the level of the electrolyte
1. boric acid ch. 12 pg. 94
12-72. nickel cadmium battery cases and drain surfaces, which have been affected by electrolyte, should be neutralized with a solution of: 1. boric acid solution 2. sodium bicarbonate 3. potassium hydroxide
3. c. diodes ch. 12 pg. 105-107
12-73. which of the following are commonly used as rectifiers in electrical circuits? a. anodes b. resistors c. diodes 1. c, and a 2. c, and b 3. c
2. rectifiers diodes are commonly used as rectifiers. they can be described as an electron check valve, allowing flow in only 1 direction ch. 12 pg. 107
12-74. diodes are used in electrical power circuits primarily as: 1. cutout switches 2. rectifiers 3. relays
3. voltage regulators within the normal operating range, the zener will function as a voltage regulator, waveform clipper, and other related functions ch. 12 pg. 106
12-75. a typical application for zener diodes is as: 1. full-wave rectifiers 2. half-wave rectifiers 3. voltage regulators
3. cannot be turned off the schematic is for a dimming light circuit the lamp is not meant to be completely turned off, it ranges from full bright to dim if an open occurred at R1, the light will not be able to be dimmed as the voltage drop will be reduced across R2, and increase the brightness at all settings. the closest correct answer is c ch. 12 pg. 110
12-76. refer to the figure. if an open condition occurs at R1, the light: 1. cannot be turned on 2. will not be altered 3. cannot be turned off
2. any input being 1 will produce a 1 output the symbol represents a logic OR gate. it is telling us that any input with a value of 1 will result in an output of 1 ch. 12 pg. 126
12-78. refer to figure (left gate) which statement concerning the logic gate depicted above is true? 1. any input being 1 will produce a 0 output 2. any put being 1 will produce a 1 output 3. all inputs must be 1 to produce a 1 output
3. when one or more inputs are 0 this symbol is a logic AND gate. it is telling us that when 1 or more inputs are 0, the output will be 0. in this logic AND gate, all 3 inputs must be 1 or the output to be 1
12-79. refer to figure. In a functional and operating circuit, the logic gate depicted in the figure will be 0: (logic gate on the right) 1. only when all inputs are 0 2. when all inputs are 1 3. when one or more inputs are 0
3. 2645 watts P (power) = I (current) x E (volts) Ohms law - E = I x R (resistance) 5 R x 23A = 115V 115V x 23A= 2645 watts ch. 12 pg. 18
12-8. How much power is being furnished to the circuit depicted in the figure? 1. 575 watts 2. 2875 watts 3. 2645 watts
3. XOR. only the XOR or exclusive OR gate will provide a high (1) output only when the inputs are different ch. 12 pg. 128
12-80. which of the following logic gates will provide an active high output when all inputs are different? 1. XNOR 2. NOR 3. XOR
12-9. which of these will cause the resistance of a conductor to decrease? 1. decrease the length or the cross sectional area 2. decrease the length or increase the cross sectional area 3. increase the length or decrease the cross sectional area
2. decrease the length or increase the cross sectional area ch. 12 pg. 19
1. be on full bright. the schematic is a dimming circuit. the up position is full bright, therefore if R2 is stuck in the up position, the light will be fully bright and not be able to dim ch. 12 pg. 110
7-77. refer to the figure. if R2 sticks in the up position, the light will: 1. be on full bright 2. be very dim 3. not illuminate
12-10. if the cross sectional area of a given conductor is increased to 4 times its original value, and the length and temperature remain constant, the resistance of the conductor will be: 1. one fourth its original value 2. four times its original value 3. found by multiplying the original resistance by the percentage increase in cross-sectional area
1. 1/4 its original value current flow capability quadrupled, so the resistance now is quartered ch. 12 pg. 20
2. 2 volts ch. 12 pg. 5
12-1. 2/1,000th of a KV = 1. 20 volts 2. 2 volts 3. 0.2 volts
2. heat when current flows through a resistive circuit, energy is dissipated in the form of heat ch. 12 pg. 22
12-11. Which of the below is the product of electrical resistance? 1. coulombs 2. heat 3. ohms
3. 450 watts to determine total power requirements, first calculate the power needed for each unit 450 watts is the closest correct answer ch. 12 pg. 22
12-12. refer to the figure. how much power must a 24 volt generator furnish to a system which contains the following loads? note: 1 horsepower = 746 watts 1. 385 watts 2. 402 watts 3. 450 watts
1. 1000 watts maintaining the same efficiency means you are getting to same input/output amount, regardless the voltage value ch. 12 pg. 22
12-13. A 12-volt electric motor has 1000 watts input and 1 horsepower output. Maintaining the same efficiency, how much input power does a 24-volt 1-horsepower electric motor require? 1. 1000 watts 2. 2000 watts 3. 3000 watts
