ACET study guide Exam 174 Questions with Verified Answers,100% CORRECT, Exams of Advanced Education

Download ACET study guide Exam 174 Questions with Verified Answers,100% CORRECT and more Exams Advanced Education in PDF only on Docsity! ACET study guide Exam 174 Questions with Verified Answers Binary is in vaules of? - CORRECT ANSWER 1 , 2, 4, 8...... so on incressed by *2 each following Octal place vaules? - CORRECT ANSWER 0-7 each digit holds a place vaule of 3 binargy digits Hex - CORRECT ANSWER 0-9 followed by A-F. A=10 each digit holds 4 in binary Binary divide by rule - CORRECT ANSWER When you divide, no remainder =0, remainder =1 Don't carry foward the remainder. Revese the reminders when translating to binary Classes of fire - CORRECT ANSWER Class A combustable metrails such as wood Class B flammable liquids & gases Class C electrical fire Class D metal fire.. flammable metals class K Cooking oils or fats When did the CET cert program begin? - CORRECT ANSWER 1965 When did the ETA initate the reneawl? - CORRECT ANSWER 1996 B+ or supply votages products are considered to be? - CORRECT ANSWER +12 to 300V DC Shaded componets on a schematics mean? - CORRECT ANSWER Only exact compents can be replaced Leakage current in electronics should not exceed? - CORRECT ANSWER 500uA Second degree skin burns should? - CORRECT ANSWER Not be treated with ice and a banadge Rules describing the fire or toxicity retardant types of cabling which may be installed in buildings is contained in? - CORRECT ANSWER NEC article 770 ESD is most decrtuive to? - CORRECT ANSWER CMOS semicondutors Lethal current is how many amps? - CORRECT ANSWER 100mA Atomic nunumber - CORRECT ANSWER Number of Protons Atmoic weight - CORRECT ANSWER number of proton and nutrons Ferrite - CORRECT ANSWER Is a common inductor core material Total Impedance in a series circuit is found by - CORRECT ANSWER Finding the net reactance and the net reistance, square each separately, add them together and then find the square root of the sum IN AC curcuit as applied voltage freq changes upward, the inductive reactance in the circuit will? - CORRECT ANSWER Incress In an AC circuit as the applied voltage frequency increases the capactive reactance in the circuit will - CORRECT ANSWER Incress In a series circuit when the inductive reactance equal the capacitor reactnces the circuit has______ Impedance - CORRECT ANSWER Minimum In a parallel circuit when the inductive reactance equals cpacitor reactance, the circuit has_______________ impedance - CORRECT ANSWER Maximum Resonance is when - CORRECT ANSWER The total of the inductive reactances in the circuit equal the toal of all capacitive reactnces _____ cells are prone to battery memory - CORRECT ANSWER NiCad interagated circuit - CORRECT ANSWER IMpedance matching device Common Base transitor - CORRECT ANSWER Highest V gain Common collector tranitor - CORRECT ANSWER Has high output impedance Common emitter - CORRECT ANSWER s Zener doides operate in? - CORRECT ANSWER Reverse bais SCR (Or Thristors) - CORRECT ANSWER Once it is turned on it can only be turned off by remove the anode potential In testing a diode, a foward-to-reverse ratio of 10-1 is indactive of a good diode? True or false - CORRECT ANSWER False Must be greater than 10 to 1 Silicon diodes require how many volts to overcome forward baise? - CORRECT ANSWER .7 tpicaly but .6 has been in some of the math for the book Germanium requries how many volts to overcome foward? - CORRECT ANSWER .3V Which part of a transitor carries the most current? - CORRECT ANSWER Emitter (Ic+Ib=Ie) What is the primary difference between an NPN and a PNP? - CORRECT ANSWER potential DC voltages are reversed. Which transistor circuit (common base, collector or common emitter) normally produces the largest voltage gain? - CORRECT ANSWER Common base Zener and varactor diodes are usually biased in what way? - CORRECT ANSWER Reverse biased, meaning the positive voltage connects to the N material. A BGA chip has which of the following: a. thru hole pins b. leads on the sides c. solder balls underneath d. both gates anodized - CORRECT ANSWER solder balls underneath Troubleshooting discrete circuits involves a knowledge of what two things? - CORRECT ANSWER How the circuit functions and how it failed. SMT stands for what? - CORRECT ANSWER Surface mount technology. When replacing a DIP chip, what is the standard practice for soldering? - CORRECT ANSWER Use an ESD static grounded soldering pencil or work station. one area where technicians will still find discrete electronic components is ________________? - CORRECT ANSWER RF equipment What basic circuit parameter makes it difficult to build integrated circuits with a high number of components to operate at super high frequencies? - CORRECT ANSWER Shunt capacitance When troubleshooting equipment that is software controlled_________. - CORRECT ANSWER Use of a computer may be required. A category 2 type of electronics equipment could be a________? - CORRECT ANSWER fax machine An example of a solid state device is a____________. - CORRECT ANSWER silicon diode. What is meant by solid-state? - CORRECT ANSWER refers to electronic components, devices, and systems based entirely on the semiconductor A four layer PN device is classified as a___________ - CORRECT ANSWER thyristor. (four layer solid-state device) How is a fuse installed in a circuit to insure proper operation: a. parallel to a load b. in series with the load c. in any way possible d. at the ground point - CORRECT ANSWER in series with the load A negative temperature coefficient thermistor will: a. increase in resistance with temperature b. decrease in resistance with temperature c. have no change in resistance with heat or cold d. increase in resistance with higher voltage - CORRECT ANSWER decrease in resistance with temperature A NiMh battery cell, when charged, has a terminal voltage of: a. 2.1 V b. 1.2 V c. 5.0 V d. 12 V - CORRECT ANSWER 1.2 volts A thermocouple has an output in the range of: a. millivolts b. microvolts c. volts d. nanovolts - CORRECT ANSWER millivolts Germanium diodes a. have .3 volts forward voltage drop b. are more often used in power supply circuits c. are more tolerant of heat than silicon diodes Voltage gain of a JFET - CORRECT ANSWER [(µ*RL)/(RL+rD)] Three of amp that yield highest power gains - CORRECT ANSWER Common cathode common source common emitter Most likely to be a linear push pull amp - CORRECT ANSWER Class B or AB Which of the following terms is associated with a commercial receiver being able to reject image frequencies - CORRECT ANSWER Selectivity Phase Locked loop - CORRECT ANSWER Can be used to recover audio from an IF in a FM receiver FCC stands for - CORRECT ANSWER Federal Communications commission A superheterodyne radio receiver is made up of - CORRECT ANSWER Intermediate frequency circuit Radio frequency Circuit Audio Frequency Circuit Mixer Circuit Which part of a superheterodyne receiver rectifies the RF carrier? - CORRECT ANSWER AF Circuit Which style of antenna radiates in the opposite directions with a pattern resembling a figure 8? - CORRECT ANSWER Yagi What frequency band is an average AM commercial broadcast radio capable of receiving? - CORRECT ANSWER 545 to 1700kHZ What is the process of imposing intelligence on a carrier wave? - CORRECT ANSWER Modulation The basic forumla for waveleng is - CORRECT ANSWER L=v/f Flexible coaxial transmission lines are ideal for what frequencies? - CORRECT ANSWER Bellow GHz Standing waves occur on a transmission line when there is an __________ between the transmission line and the load - CORRECT ANSWER impedance mismatch Maxium power transfer to the load occurs when the load impedance matches that of the transmission line - CORRECT ANSWER True Antenna resonance is the characteristic that permits _________ radiation of the transmitted signal - CORRECT ANSWER maxium Space wave are ideal for what frequency of communications - CORRECT ANSWER Line-of-sight UHF (Ultra high Freq) Electromagnetic field polarization is determined by the orientation of what part of the electromagnetic wave? - CORRECT ANSWER Electric lines of force Quarter-wave antennas must be ______ at one end for the resonance at the desired frequency - CORRECT ANSWER Grounded On hook DC voltage on a telephone local loop is - CORRECT ANSWER -48V Dial tone is composed of these two frequnces - CORRECT ANSWER 350+440 Hz The DTMF tones for the number 5 on a telephone keypad is - CORRECT ANSWER 770 + 1336Hz A trunk connects - CORRECT ANSWER Two central offices a CLCEC is - CORRECT ANSWER A cable TV company Wireless provider CLCEC - CORRECT ANSWER Competitive local exchange carrier The maximum bit rate available on a T-1 transmission system is - CORRECT ANSWER 1.544 Mbps Oscillators use quartz crystals that generate output by the - CORRECT ANSWER Piezoelectric effect Analog telephone lines have what DC voltage level across the tip and ring when off the hook? - CORRECT ANSWER -48V DC Cables of different impedance may be combined for short runs? - CORRECT ANSWER False The bandwidth of standard definition analog TV signal is - CORRECT ANSWER 6MHz What radio receiver section determines the dario's inherent noise level? - CORRECT ANSWER RF Carbon Microphones are much like variable - CORRECT ANSWER Resistors In telecommunications work, ______ is replacing twisted pair cabling - CORRECT ANSWER Both fiber opitcs and wireless Wave guides are not utilized at HF or VHF frequencies because - CORRECT ANSWER Large wave guide dimensions required at lower frequencies are not practical A logic 1, for a TTL device is - CORRECT ANSWER more than 2 volts A logic 1 for a CMOS device connected to a 5V supply is - CORRECT ANSWER more than 3.5 volts A green light usally indicates - CORRECT ANSWER A logic high Another name for an astable multivibrator is - CORRECT ANSWER Free running The three basic logic gates are - CORRECT ANSWER AND, OR , NOT increases the effective input impedance Decreased the signal to the scope Retrace blanking in an oscilloscope is - CORRECT ANSWER applied to the Z-axi To accurately measure a resistance across a transistor emitter-base junction, use a - CORRECT ANSWER low ohms function An inductor shorted turn can be detected reliably using - CORRECT ANSWER Ringer test An AC voltmeter will measure a non-sine wave signal accurately only if - CORRECT ANSWER It is a true RMS meter A type of transformer which has 1:1 turns ratio - CORRECT ANSWER provides a floating secondary reference point A shock hazards exit especially - CORRECT ANSWER A full-wave bridge rectifier connected directly to the AC power source SA DC voltmeter multiplier roister - CORRECT ANSWER Limits the meter movement current to its full scale vaule A simple DC voltmeter with a 200 uA movement needs to have how much internal resistance on its voltage range? - CORRECT ANSWER 250K Ω The solder traditionally used is a metal alloy consiting of zin and copper - CORRECT ANSWER false The most common solder used by electronics technicians consists of - CORRECT ANSWER 60% tin and 40% lead The proper process for soldering two objects together - CORRECT ANSWER Heat both surfaces at the same time and apply solder Overheating the compnet lead will likey damge - CORRECT ANSWER Transistors and diodes first Tinning of ____ makes the best connection - CORRECT ANSWER Soldier iron tip Stranded wire component leads All the above is correct Movement of any componet of the solder connection before the solder has harded - CORRECT ANSWER Results in a poor electrical connection Which device is capable of causing magnetic or inductive damage to electronic deceives? - CORRECT ANSWER Soldering gun To remove solder from a join using copper braid - CORRECT ANSWER Touch the join with the brad- heat it and let the solder wick up the braid The best way to remove an IC chip which is solder into a PC board is to - CORRECT ANSWER Use a desoldering adapter tip which heats all the pins simultaneously Surface mount components do not require mechanical bonding because - CORRECT ANSWER The components are so small solder is enough to hold in place A circle is obtained on the scope when - CORRECT ANSWER two sine waves that are 90 degrees out of phase fed to the vertical and horizontal inputs Which frequency is most commonly used for audio troubleshooting? - CORRECT ANSWER 1 KHz Why is a couple capacitor used when troubleshooting with signal injection - CORRECT ANSWER Block DC level present Which would be the likely cause of a hum in an amplifier but only present when the CD position is selected? - CORRECT ANSWER Bad shielded cable from the CD player