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Instructed by Rich Bugarin W6EC Hi-Landers Ham Class Instructed by Rich Bugarin W6EC
Sub-element 5 of 10
Ham Radio Technician Class Exam preparation Power Point created by Rich Bugarin W6EC. Effective July 1, 2018 and is valid until June 30, 2022. Please send suggested changes to this presentation to: w6ec@thebugarins.com
Study Hints I suggest you read each question and only the correct answer. Read through the complete question pool at least three times before you attempt taking a practice exams. For higher impact and better results read the correct answer first then the question and again the correct answer. The key to passing the exam is to get the most questions correct using the above method the correct response will often jump out at you on test day even if you don’t remember the question.
Text Color Black: Original/Official questions and information in original format (unaltered). Red: Original information text color simply changed to highlight subject. Blue: Notes and information added by Rich (W6EC).
SUBELEMENT T5 – Electrical principles, math for electronics, electronic principles, Ohm’s Law [4 Exam Questions - 4 Groups]
Basic Electronics Info E = Electro Motive Force Measured in Volts = V I = Intensity of Current Flow Measured Amperes (Amps) = A R = Resistance Measured in Ohms = P = Power Measured in Watts = W
Ohms Law To calculate Volts when you know the Amp and Ohm value. E= I x R
Ohms Law To calculate Amps when you know the Volt and Ohm value. I = E ÷ R I = E/R I = } Three ways of writing the same formula. E R
Ohms Law To calculate Ohms when you know the Volt and Amp value. R = E ÷ I
Ohms Law E= I x R I = E / R R = E / I Therefore the three ohms law formulas are: E= I x R I = E / R R = E / I The three formulas can easily be remembered by placing them in a circular form shown on the next slide.
Ohms Law E I R
Ohms Law E I R To find the Voltage formula cover the “E” leaving IxR
Ohms Law E I R To find the Amp formula cover the “I” leaving E/R
Ohms Law E I R To find the Ohm formula cover the “R” leaving E/I
Calculating Voltage I=2A R=12 E=? E=IxR 2x12 = 24 Answer: E = 24V
Calculating Amps I=? R=12 E=24V I=E/R 24/12 = 2 Answer: I = 2A
Calculating Ohms I=2A R=? E=24V R=E/I 24/2 = 12 Answer: R = 12
Series Circuit Key features: All components are wired stringed together having a single current path (current is the same through out the circuit). Note; there are no branch points.
Parallel Circuit Key Factors: Components are wired in separate branches and operates independent from each other. Each component gets the same voltage. Cars are wired this way so each component receives 12 volts.
T5A - Electrical principles, units, and terms: current and voltage; conductors and insulators; alternating and direct current; series and parallel circuits #15 of 35
T5A01 Electrical current is measured in which of the following units? Volts B. Watts C. Ohms D. Amperes Current = Amps (flow of Electrons)
T5A02 Electrical power is measured in which of the following units? Volts B. Watts C. Ohms D. Amperes Power = Watts A unit of total work
T5A03 What is the name for the flow of electrons in an electric circuit? A. Voltage B. Resistance C. Capacitance D. Current Current = Amps (I= Intensity of Electron Flow)
T5A04 What is the name for a current that flows only in one direction? A. Alternating current B. Direct current C. Normal current D. Smooth current
T5A05 What is the electrical term for the electromotive force (EMF) that causes electron flow? A. Voltage B. Ampere-hours C. Capacitance D. Inductance Electromotive Force (EMF) = Volts (Push or pressure, similar to PSI)
T5A06 How much voltage does a mobile transceiver usually require? A. About 12 volts B. About 30 volts C. About 120 volts D. About 240 volts
T5A07 Which of the following is a good electrical conductor? A. Glass B. Wood C. Copper D. Rubber
T5A08 Which of the following is a good electrical insulator? A. Copper B. Glass C. Aluminum D. Mercury
T5A09 What is the name for a current that reverses direction on a regular basis? A. Alternating current B. Direct current C. Circular current D. Vertical current
T5A10 Which term describes the rate at which electrical energy is used? A. Resistance B. Current C. Power D. Voltage Power = Watts A unit of total work or use of energy
T5A11 What is the basic unit of electromotive force? A. The volt B. The watt C. The ampere D. The ohm Electromotive Force (EMF) = Volts (Push or pressure, similar to PSI)
T5A12 What term describes the number of times per second that an alternating current reverses direction? A. Pulse rate B. Speed C. Wavelength D. Frequency Frequency is measured in Hertz = Hz, it is a measure of how many cycles occur in one second
T5A13 In which type of circuit is current the same through all components? A. Series B. Parallel C. Resonant D. Branch
T5A14 In which type of circuit is voltage the same across all components? A. Series B. Parallel C. Resonant D. Branch
T5B - Math for electronics: conversion of electrical units; decibels; the metric system
METRIC PREFIX Metric prefixes are used to shorten a number to allow easer handling and communications of the value. Metric prefixes were originally used in the scientific and electronics sectors, but with high tech equipment all around us it has found its way into every day life. An example is a computer has 512,000,000 bytes of memory, it is easer to say 512 Mega Bytes and very easy to write it as 512Mb. Following is the most common metric prefixes used in electronics and a convenient chart to organize them.
Metric Prefix Units (None) 000. Units = Basic unit of measurement with no prefix. Example: 5 volts = 5V
Metric Prefix K Kilo Units (None) 000, 000. Kilo = Thousand = 1,000. Example: 5,000 Volts = 5KV
Metric Prefix M K Mega Kilo Units (None) 000, 000. Mega = Million = 1,000,000. Example: 64,000,000 Bytes = 64Mb
Metric Prefix G M K Giga Mega Kilo Units (None) 000, 000. Giga = Billion = 1,000,000,000. Example: 80,000,000,000 Bytes = 80Gb
Metric Prefix T G M K Tera Giga Mega Kilo Units (None) 000, 000. Tera = Trillion = 1,000,000,000,000. Example: 8,000,000,000,000 Bytes = 8Tb
Kilo, Mega Giga and Tera are conveniently spaced 1000 apart from each other. Mega is a thousand times larger than Kilo. Mega is a thousand times smaller than Giga. Kilo, Mega Giga and Tera are all used to represent numbers that are larger than the number 1.
Some times we will be dealing with numbers that are smaller than the number 1. Lets say we have a meter stick and we brake it into a thousand pieces, we then keep 5 of the thousand pieces we can express that as 5/1000 or 0.005 meters. Using metric prefixes it is known as 5 milli meters and written as 5mm.
Metric Prefix T G M K m Tera Giga Mega Kilo Units Milli (None) 000, 000. Milli = Thousandth = 0.001 or 1/1,000. Example: 0.008 Amps = 8mA
Metric Prefix T G M K m µ u Tera Giga Mega Kilo Units Milli Micro (None) m µ Or u Tera Giga Mega Kilo Units Milli Micro 000, 000. Micro = Millionth = 0.000,001 or 1/1,000,000. Micro is represented by the Greek Letter µ Example: 0.000,009 meters = 9µm
Metric Prefix T G M K m µ u n Tera Giga Mega Kilo Units Milli Micro (None) m µ Or u n Tera Giga Mega Kilo Units Milli Micro Nano 000, 000. Nano = Billionth = 0.000,000,001 Example: 0.000,000,025 seconds = 25ns
Metric Prefix T G M K m µ u n p Tera Giga Mega Kilo Units Milli Micro (None) m µ Or u n p Tera Giga Mega Kilo Units Milli Micro Nano Pico 000, 000. Pico = Trillionth = 0.000,000,000,001 Example: 0.000,000,000,750 Farads = 750pF
Milli, Micro, Nano and Pico are also conveniently spaced 1000 apart from each other. Micro is a thousand times smaller than Milli. Micro is a thousand times larger than Nano. Milli, Micro, Nano and Pico are all used to represent numbers that are smaller than the number 1.
Prefix Conversion The Prefix chart we have been using can also be used as a visual aid in converting a number from one metric prefix to another such as from Kilo to Mega. The following pages show examples of how to convert the number.
Prefix Conversion T G M K m µ u n p Tera Giga Mega Kilo Units Milli (None) m µ Or u n p Tera Giga Mega Kilo Units Milli Micro Nano Pico 000, 000. 45,000. Convert 45,000 V to KV 45.000KV = 45.KV
Prefix Conversion T G M K m µ u n p Tera Giga Mega Kilo Units Milli (None) m µ Or u n p Tera Giga Mega Kilo Units Milli Micro Nano Pico 000, 000. 5,000. Convert 5,000.mA to A 5,000.mA = 5.000A = 5.A
Prefix Conversion T G M K m µ u n p Tera Giga Mega Kilo Units Milli (None) m µ Or u n p Tera Giga Mega Kilo Units Milli Micro Nano Pico 000, 000. 0.400 Convert 0.4A to mA 0.4A = 0.400A = 400mA
Prefix Conversion T G M K m µ u n p Tera Giga Mega Kilo Units Milli (None) m µ Or u n p Tera Giga Mega Kilo Units Milli Micro Nano Pico 000, 000. 000,900. Convert 900pF to µF 900pF = 000,900.pF = 0.0009µF
Prefix Conversion T G M K m µ u n p Tera Giga Mega Kilo Units Milli (None) m µ Or u n p Tera Giga Mega Kilo Units Milli Micro Nano Pico 000, 000. 27.000 Convert 27MHz to KHz 27MHz = 27.000MHz = 27,000.KHz
T5B01 How many milliamperes is 1.5 amperes? A. 15 milliamperes B. 150 milliamperes C. 1,500 milliamperes D. 15,000 milliamperes (See Next Slide)
T G M K m µ u n p Tera Giga Mega Kilo Units Milli Micro Nano Pico (None) m µ Or u n p Tera Giga Mega Kilo Units Milli Micro Nano Pico 000, 000. 1.500 Convert 1.5A to mA 1.5A = 1.500A = 1,500mA
T5B02 What is another way to specify a radio signal frequency of 1,500,000 hertz? A. 1500 kHz B. 1500 MHz C. 15 GHz D. 150 kHz (See Next Slide)
T G M K m µ u n p Tera Giga Mega Kilo Units Milli Micro Nano Pico (None) m µ Or u n p Tera Giga Mega Kilo Units Milli Micro Nano Pico 000, 000. 1,500,000. Convert 1,500,000 Hz to KHz 1,500.000KHz = 1,500.KHz
T5B03 How many volts are equal to one kilovolt? A. One one-thousandth of a volt B. One hundred volts C. One thousand volts D. One million volts Kilo = Thousand = 1,000.
T5B04 How many volts are equal to one microvolt? A. One one-millionth of a volt B. One million volts C. One thousand kilovolts D. One one-thousandth of a volt Micro = Millionth = 0.000,001 or 1/1,000,000.
T5B05 Which of the following is equivalent to 500 milliwatts? A. 0.02 watts B. 0.5 watts C. 5 watts D. 50 watts (See Next Slide)
T G M K m µ u n p Tera Giga Mega Kilo Units Milli Micro Nano Pico (None) m µ Or u n p Tera Giga Mega Kilo Units Milli Micro Nano Pico 000, 000. 500. Convert 500.mW to W 500.mW = .5W = 0.5W
T5B06 If an ammeter calibrated in amperes is used to measure a 3000-milliampere current, what reading would it show? A. 0.003 amperes B. 0.3 amperes C. 3 amperes D. 3,000,000 amperes (See Next Slide)
T G M K m µ u n p Tera Giga Mega Kilo Units Milli Micro Nano Pico (None) m µ Or u n p Tera Giga Mega Kilo Units Milli Micro Nano Pico 000, 000. 3,000. Convert 3,000.mA to A 3,000.mA = 3.000A = 3.A
T5B07 If a frequency readout calibrated in megahertz shows a reading of 3.525 MHz, what would it show if it were calibrated in kilohertz? A. 0.003525 kHz B. 35.25 kHz C. 3525 kHz D. 3,525,000 kHz (See Next Slide)
T G M K m µ u n p Tera Giga Mega Kilo Units Milli Micro Nano Pico (None) m µ Or u n p Tera Giga Mega Kilo Units Milli Micro Nano Pico 000, 000. 3.525 Convert 3.525MHz to KHz 3.525MHz =3,525.KHz
T5B08 How many microfarads are 1,000,000 picofarads? A. 0.001 microfarads B. 1 microfarad C. 1000 microfarads D. 1,000,000,000 microfarads (See Next Slide)
T G M K m µ u n p Tera Giga Mega Kilo Units Milli Micro Nano Pico (None) m µ Or u n p Tera Giga Mega Kilo Units Milli Micro Nano Pico 000, 000. 1,000,000. Convert 1,000,000pF to µF 1,000,000pF = 1.000,000µF = 1µF
T5B09 What is the approximate amount of change, measured in decibels (dB), of a power increase from 5 watts to 10 watts? A. 2 dB B. 3 dB C. 5 dB D. 10 dB When the power doubles this is known as a 3dB change 5W doubled is 10W
T5B10 What is the approximate amount of change, measured in decibels (dB), of a power decrease from 12 watts to 3 watts? A. -1 dB B. -3 dB C. -6 dB D. -9 dB 3W doubled is 6W, 6W doubled is 12W 3 Watts is doubled twice to get to 12W. Each time power is doubled = 3dB Doubled twice is 3dB X 2 = 6dB
T5B11 What is the approximate amount of change, measured in decibels (dB), of a power increase from 20 watts to 200 watts? A. 10 dB B. 12 dB C. 18 dB D. 28 dB 20 goes into 200 10 times. (200/20=10) A 10X increase of power is 10dB. (dB is a 10log system of power levels)
T5B12 Which of the following frequencies is equal to 28,400 kHz? A. 28.400 MHz B. 2.800 MHz C. 284.00 MHz D. 28.400 kHz Kilo is a Thousand the number is 28,4000 Thousand is also known as 28.400 Million, Mega is a Million.
T5B13 If a frequency readout shows a reading of 2425 MHz, what frequency is that in GHz? A. 0.002425 GHZ B. 24.25 GHz C. 2.425 GHz D. 2425 GHz Move the decimal point three places to the left to convert Mega to Giga
T5C - Electronic principles: capacitance; inductance; current flow in circuits; alternating current; definition of RF; definition of polarity; DC power calculations; impedance #17 of 35
T5C01 What is the ability to store energy in an electric field called? A. Inductance B. Resistance C. Tolerance D. Capacitance
T5C02 What is the basic unit of capacitance? A. The farad B. The ohm C. The volt D. The henry
T5C03 What is the ability to store energy in a magnetic field called? A. Admittance B. Capacitance C. Resistance D. Inductance
T5C04 What is the basic unit of inductance? A. The coulomb B. The farad C. The henry D. The ohm
T5C05 What is the unit of frequency? A. Hertz B. Henry C. Farad D. Tesla
T5C06 What does the abbreviation “RF” refer to? A. Radio frequency signals of all types B. The resonant frequency of a tuned circuit C. The real frequency transmitted as opposed to the apparent frequency D. Reflective force in antenna transmission lines
T5C07 A radio wave is made up of what type of energy? A. Pressure B. Electromagnetic C. Gravity D. Thermal
P= I x E To calculate Watts when you know the Amp and Volt value. Watts Law To calculate Watts when you know the Amp and Volt value. P= I x E
E = P ÷ I To calculate Volts when you know the Watt and Amp value. Watts Law To calculate Volts when you know the Watt and Amp value. E = P ÷ I
I = P ÷ E To calculate Amps when you know the Watt and Volt value. Watts Law To calculate Amps when you know the Watt and Volt value. I = P ÷ E
Watts Law P= I x E E = P/I I = P/E Therefore the three watts law formulas are: P= I x E E = P/I I = P/E The three formulas can easily be remembered by placing them in a circular form shown on the next page.
Watts Law P I E
Watts Law P I E To find the Wattage formula cover the “P” leaving IxE
Watts Law P I E To find the Current formula cover the “I” leaving P/E
Watts Law P I E To find the Voltage formula cover the “E” leaving P/I
Calculating Wattage I=2A E=24V P=? P=IxE 2x24 = 48 Answer: P = 48W
Calculating Amperage I=? E=24V P=48W I=P/E 48/24 = 2 Answer: I = 2A
Calculating Voltage I=2A E=? P=48W E=P/I 48/2 = 24 Answer: E = 24V
T5C08 What is the formula used to calculate electrical power in a DC circuit? A. Power (P) equals voltage (E) multiplied by current (I) B. Power (P) equals voltage (E) divided by current (I) C. Power (P) equals voltage (E) minus current (I) D. Power (P) equals voltage (E) plus current (I) P I E P = I x E
T5C09 How much power is being used in a circuit when the applied voltage is 13.8 volts DC and the current is 10 amperes? A. 138 watts B. 0.7 watts C. 23.8 watts D. 3.8 watts P = I x E 10 x 13.8 = 138 P I E
T5C10 How much power is being used in a circuit when the applied voltage is 12 volts DC and the current is 2.5 amperes? A. 4.8 watts B. 30 watts C. 14.5 watts D. 0.208 watts P = I x E 2.5 x 12 = 30 P I E
T5C11 How many amperes are flowing in a circuit when the applied voltage is 12 volts DC and the load is 120 watts? A. 0.1 amperes B. 10 amperes C. 12 amperes D. 132 amperes I = P / E 120 / 12 = 10 P I E
T5C12 What is meant by the term impedance? A. It is a measure of the opposition to AC current flow in a circuit B. It is the inverse of resistance C. It is a measure of the Q or Quality Factor of a component D. It is a measure of the power handling capability of a component
T5C13 What are the units of impedance? A. Volts B. Amperes C. Coulombs D. Ohms
T5C14 What is the proper abbreviation for megahertz? A. mHz B. mhZ C. Mhz D. MHz Capital “M” for Mega Capital “H” lower case “z” for Hertz
T5D – Ohm’s Law: formulas and usage; components in series and parallel #18 of 35
T5D01 Current = Amps (I = intensity of Electrons flow) What formula is used to calculate current in a circuit? A. Current (I) equals voltage (E) multiplied by resistance (R) B. Current (I) equals voltage (E) divided by resistance (R) C. Current (I) equals voltage (E) added to resistance (R) D. Current (I) equals voltage (E) minus resistance (R) E I R
T5D02 E = Electro Motive Force Measured in Volts = V What formula is used to calculate voltage in a circuit? A. Voltage (E) equals current (I) multiplied by resistance (R) B. Voltage (E) equals current (I) divided by resistance (R) C. Voltage (E) equals current (I) added to resistance (R) D. Voltage (E) equals current (I) minus resistance (R) E I R
T5D03 Resistance (R) = Ohms = Ω (Opposition to current flow) What formula is used to calculate resistance in a circuit? A. Resistance (R) equals voltage (E) multiplied by current (I) B. Resistance (R) equals voltage (E) divided by current (I) C. Resistance (R) equals voltage (E) added to current (I) D. Resistance (R) equals voltage (E) minus current (I) E I R
T5D04 What is the resistance of a circuit in which a current of 3 amperes flows through a resistor connected to 90 volts? A. 3 ohms B. 30 ohms C. 93 ohms D. 270 ohms R = E / I 90 / 3 = 30 E I R
T5D05 What is the resistance in a circuit for which the applied voltage is 12 volts and the current flow is 1.5 amperes? A. 18 ohms B. 0.125 ohms C. 8 ohms D. 13.5 ohms R = E / I 12 / 1.5 = 8 E I R
T5D06 What is the resistance of a circuit that draws 4 amperes from a 12-volt source? A. 3 ohms B. 16 ohms C. 48 ohms D. 8 Ohms R = E / I 90 / 3 = 30 E I R
T5D07 What is the current flow in a circuit with an applied voltage of 120 volts and a resistance of 80 ohms? A. 9600 amperes B. 200 amperes C. 0.667 amperes D. 1.5 amperes I = E / R 120 / 80 = 1.5 E I R
T5D08 What is the current flowing through a 100-ohm resistor connected across 200 volts? A. 20,000 amperes B. 0.5 amperes C. 2 amperes D. 100 amperes I = E / R 200 / 100 = 2 E I R
T5D09 What is the current flowing through a 24-ohm resistor connected across 240 volts? A. 24,000 amperes B. 0.1 amperes C. 10 amperes D. 216 amperes I = E / R 240 / 24 = 10 E I R
T5D10 What is the voltage across a 2-ohm resistor if a current of 0.5 amperes flows through it? A. 1 volt B. 0.25 volts C. 2.5 volts D. 1.5 volts E = I x R 0.5 x 2 = 1 E I R
T5D11 What is the voltage across a 10-ohm resistor if a current of 1 ampere flows through it? A. 1 volt B. 10 volts C. 11 volts D. 9 volts E = I x R 1 x 10 = 10 E I R
T5D12 What is the voltage across a 10-ohm resistor if a current of 2 amperes flows through it? A. 8 volts B. 0.2 volts C. 12 volts D. 20 volts E = I x R 2 x 10 = 20 E I R
T5D13 What happens to current at the junction of two components in series? A. It divides equally between them B. It is unchanged C. It divides based on the on the value of the components D. The current in the second component is zero Current is the same in all parts of a series circuit
T5D14 What happens to current at the junction of two components in parallel? A. It divides between them dependent on the value of the components B. It is the same in both components C. Its value doubles D. Its value is halved
T5D15 What is the voltage across each of two components in series with a voltage source? A. The same voltage as the source B. Half the source voltage C. It is determined by the type and value of the components D. Twice the source voltage
T5D16 What is the voltage across each of two components in parallel with a voltage source? A. It is determined by the type and value of the components B. Half the source voltage C. Twice the source voltage D. The same voltage as the source Voltage is the same in all branches of a parallel circuit
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