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2014 General

TESTGUIDE STUDY & PREPARE Pass your FAA Knowledge Exam and know what is essential to become a safe, competent AMT— from the most trusted source in aviation training

General Test Guide 

2014 Edition Aviation Supplies & Academics, Inc. 7005 132nd Place SE Newcastle, Washington 98059-3153 425.235.1500 www.asa2fy.com  © 2013 Aviation Supplies & Academics, Inc. All rights reserved. No part o the explanations to the FAA questions may be reproduced in any manner whatsoever without written permission o the publisher. FAA questions herein are rom United States government sources and contain current inormation as o: June 2013 None o the material in this publication supersedes any documents, procedures or regulations issued by the Federal Aviation Administration. ASA assumes no responsibility or any errors or omissions. Neither is any liability assumed or damages resulting rom the use o the inormation contained herein.

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Contents Updates and Practice Tests ....................................................................................v Preface .........................................................................................................................vii Instructions Excerpt from FAA-G-8082-3 ....................................................................ix Learning Statement Codes ....................................................................................xv Knowledge Exam References ............................................................................. xix General Test Questions, Explanations, Answers and References .............................. 1–124 Oral and Practical Study Guide ......................................................................... 125

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General Test Questions, Explanations, Answers and References Answers are printed at the bottom o the page, with other coded items as explained below:

This is the question number. The brackets enclose the letter answer selected by ASA’s researchers. (For those questions or which none o the answer choices provide an accurate response, we have noted [X] as the Answer.)

8001 [C] (031)

AMT-G Ch 4

The parentheses enclose the appropriate Learning Statement Code (LSC)—reer to Page xv. FAA Learning Statement Codes have letter-identiying prefxes, but or reerence purposes in this book the letter prefx (“AMG”) is omitted and only the number-identiying portion o the code is shown in parentheses. The reerence ollowing the Learning Statement Code is the source rom which the answer was derived. The meanings o these abbreviations are ound on Page xix. The number ollowing the abbreviations is the specifc chapter within that source to study or more inormation about the derived answer.

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Questions, Explanations, Answers & References

8001. The working voltage o a capacitor in an ac circuit

8002-2. Electrostatic felds are also known as

should be

A— Dielectric felds. B— Electrostatic felds. C— Static felds.

A— equal to the highest applied voltage. B— at least 20 percent greater than the highest applied voltage. C— at least 50 percent greater than the highest applied voltage. The working voltage o a capacitor is the highest voltage  that can be steadily applied to it without the danger o the  dielectric breaking down. The working voltage depends upon the material used  as the dielectric and on its thickness. A capacitor used in an AC circuit should have a work-  ing voltage at least 50 percent greater than the highest  voltage that will be applied to it. 8002. The term that describes the combined resistive

orces in an ac circuit is A— resistance. B— reactance. C— impedance. Impedance, whose symbol is Z, is the combined resistive  orce in an AC circuit. There are three types o resistive orces in an AC circuit:  inductive reactance, which causes the current to lag the  voltage, capacitive reactance, which causes the current to  lead the voltage, and resistance, which allows the current  and voltage to remain in phase. Inductive and capacitive reactance are 180° out o  phase, and they cancel each other. Impedance is the vector sum o the resistance and the  total reactance in the circuit; it is expressed in ohms and  is ound by the ormula: 

8002-1. What is the opposition to the ow o AC produced

by a magnetic feld with generated back voltage (EMF) called? A— Inductive reactance. B— Capacitive reactance. C— Mutual inductance.

8003. The basis or transormer operation in the use o

alternating current is mutual A— inductance. B— capacitance. C—reactance. A transormer operates on the basis o mutual inductance. The changing current in the primary windings produces a  changing magnetic eld whose fux cuts across the turns  o the secondary winding and induces a voltage into it. 8004. The opposition oered by a coil to the ow o alter-

nating current is called (disregard resistance) A— impedance. B— reluctance. C— inductive reactance. When alternating current fows in a coil o wire, the chang-  ing lines o fux cutting across the turns o wire in the coil  induce a voltage in it. The polarity o this voltage (the  counter EMF) is opposite to the polarity o the voltage  that caused it. The counter EMF decreases the total voltage across  the coil, and this decreases the current fowing through it. This opposition to the fow o alternating current is called  inductive reactance (X L ), and it is measured in ohms. It  opposes the fow o current, but it does not cause heat  nor use any power. 8005. An increase in which o the ollowing actors will

cause an increase in the inductive reactance o a circuit?

Alternating current is in a constant state o change; the  eects o the magnetic elds are a continuously inducted  voltage opposition to the current in the circuit. This oppo-  sition is called inductive reactance, symbolized by X L, and is measured in ohms just as resistance is measured. Inductance is the property o a circuit to oppose any  change in current and it is measured in henries. Inductive  reactance is a measure o how much the countering EMF  in the circuit will oppose current variations. Answers

A eld o orce exists around a charged body. This is an  electrostatic eld (sometimes called a dielectric eld) and  it is represented by lines that extend in all directions rom  the charged body which terminate where there is an equal  and opposite charge.

A— Inductance and requency. B— Resistance and voltage. C— Resistance and capacitive reactance. The inductive reactance (X L ) in an AC circuit is increased  when either the requency o the alternating current or the  inductance o the circuit is increased. Resistance, voltage, or capacitive reactance have no  eect on the inductive reactance o a circuit. The ormula or inductive reactance is:  X L = 2 π L

Note: All Learning Statement Codes (in parentheses) are preceded by “AMG.” See explanation on Page 1.

8001 [C] (031) AMT-G Ch 4 8003 [A] (015) AMT-G Ch 4

8002 [C] (031) AMT-G Ch 4 8004 [C] (031) AMT-G Ch 4 Fast-Track Series

8002-1 [A] (102) FAA-H-8083-30 8005 [A] (031) AMT-G Ch 4

8002-2 [A] (031) FAA-H-8083-30

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Questions, Explanations, Answers & References

8006. (Reer to Figure 1.) When dierent rated capacitors

8008. The amount o electricity a capacitor can store is

are connected in series in a circuit, the total capacitance is

directly proportional to the

A— less than the capacitance o the lowest rated capacitor. B— greater than the capacitance o the highest rated capacitor. C— equal to the sum o all the capacitances.

A— distance between the plates and inversely proportional to the plate area. B— plate area and is not aected by the distance between the plates. C— plate area and inversely proportional to the distance between the plates. Three actors aect the amount o electricity a capacitor  can store:  1. The area o the plates. The larger the plate area, the  greater the capacity.

When capacitors o dierent values are connected in  series, the total capacitance is less than that o the lowest  rated capacitor. 8006-1. Capacitors are sometimes used in dc circuits to

A— counteract inductive reactance at specifc locations. B— smooth out slight pulsations in current/voltage. C— assist in stepping voltage and current up and/or down. Capacitors store electrical charges and are sometimes  used in DC circuits to smooth out slight pulsations in the  current or voltage. They accept electrons when there is  an excess and release them back into the circuit when  the values decrease.

2. The thickness o the dielectric (the distance between  the plates). The closer the plates are together, the  stronger the electrical eld will be and the greater the  capacity. 3. The material rom which the dielectric is made (its  dielectric constant). The higher the dielectric constant, the greater the capacity. 8009. (Reer to Figure 2.) What is the total capacitance o

a certain circuit containing three capacitors with capacitances o .02 microarad, .05 microarad, and .10 microarad, respectively? A— .170 µF. B— 0.125 pF. C— .0125 µF.

8007. In an ac circuit, the eective voltage is

A— equal to the maximum instantaneous voltage. B— greater than the maximum instantaneous voltage. C— less than the maximum instantaneous voltage. The eective voltage o sine wave alternating current is  0.707 time its peak voltage. The eective voltage, also called the root-mean-square  (rms) voltage, is the voltage measured by most o the AC  voltmeters. Peak voltage is measured with either a special  peak voltmeter or an oscilloscope.

When a 0.02-microarad, a 0.05-microarad, and a  0.10-microarad capacitor are connected in series, the  total capacitance is 0.0125 microarad.

Answers

8006 [A] (031) AMT-G Ch 4 8009 [C] (031) AMT-G Ch 4 4

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8006-1 [B] (031) AMT-G Ch 4

8007 [C] (031) AMT-G Ch 4

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8008 [C] (031) AMT-G Ch 4

Questions, Explanations, Answers & References

8009-1. (Reer to Figure 2.) What is the total capacitance

8011. When dierent rated capacitors are connected in

o a circuit containing three capacitors in parallel with capacitances o .02 microarad, .05 microarad, and .10 microarad, respectively?

parallel in a circuit, the total capacitance is

A— .170 µF. B— 0.125 µF. C— .0125 µF. You do not need to reer to Figure 2 to answer this question. Instead, use the ormula C T = C 1 + C 2 + C 3.  When capaci-  tors are connected together in  parallel , the plate area o  all the capacitors add together and the total capacitance  is the sum o the individual capacitances. .02 + .05 + .10 = .170 µF 

(Note: C T = C1 + C2 + C3 . . .) A— less than the capacitance o the lowest rated capacitor. B— equal to the capacitance o the highest rated capacitor. C— equal to the sum o all the capacitances. When capacitors are connected in parallel, the eective  area o the plates add, and the total capacitance is the  sum o the individual capacitances. 8012. When inductors are connected in series in a circuit,

8009-2. Convert arads to microarads by

A— multiplying arads by 10 to the power o 6 B— multiplying picoarads by 10 to the power o 6 C— multiplying microarads by 10 to the power o 6 Each arad is equal to 10 6 microarads. Example: 2 arads  is equal to 2 × 10 6  (2,000,000) microarads. 8009-3. Convert arads to picoarads by:

A— multiplying arads by 10 to the power o 12 B— multiplying microarads by 10 to the power o -12 C— multiplying picoarads by 10 to the power o 12 Each arad is equal to 10 12 picoarads. Example: 2 arads  is equal to 2 × 10 12  (2,000,000,000) picoarads.

the total inductance is (where the magnetic felds o each inductor do not aect the others) (Note: L T = L 1 + L 2 + L3 . . .) A— less than the inductance o the lowest rated inductor. B— equal to the inductance o the highest rated inductor. C— equal to the sum o the individual inductances. When several inductors are connected together in such a  way that there is no inductive coupling, the total inductance  is the sum o the individual inductances. 8013. (Reer to Figure 3.) When more than two induc-

tors o dierent inductances are connected in parallel in a circuit, the total inductance is A— less than the inductance o the lowest rated inductor. B— equal to the inductance o the highest rated inductor. C— equal to the sum o the individual inductances.

8010. Unless otherwise specifed, any values given or

current or voltage in an ac circuit are assumed to be A— instantaneous values. B— eective values. C— maximum values. Almost all measuring instruments used or electrical  system servicing measure the eective (rms) values o  alternating current. Unless peak values, peak-to-peak values, or average  values are specically called out, eective values are  assumed.

When two or more inductors having dierent inductances  are connected in parallel, the total inductance is less than  the inductance o the lowest rated inductor.

Answers

8009-1 [A] (031) AMT-G Ch 4 8011 [C] (031) AMT-G Ch 4

8009-2 [A] (102) AMT-G Ch 4 8012 [C] (015) AMT-G Ch 4 Fast-Track Series

8009-3 [A] (102) AMT-G Ch 4 8013 [A] (031) AMT-G Ch 4

8010 [B] (031) AMT-G Ch 4

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