fundamentals of electricity franklin county amateur radio club technician class license course class...
TRANSCRIPT
![Page 1: Fundamentals of Electricity Franklin County Amateur Radio Club Technician Class License Course Class 3 – Fundamentals of Electricity Bob Solosko W1SRB](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e395503460f94b2ab8c/html5/thumbnails/1.jpg)
Fundamentals of ElectricityFundamentals of Electricity
Franklin County Amateur Radio ClubFranklin County Amateur Radio Club
Technician Class License CourseTechnician Class License Course
Class 3 – Fundamentals of ElectricityClass 3 – Fundamentals of Electricity
Bob Solosko W1SRBBob Solosko W1SRB
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Fundamentals of ElectricityFundamentals of Electricity
• All materials are made up of atoms• Atoms are composed of protons, neutrons and electrons
• electrons have a positive charge• protons have a negative charge
• In some materials, electrons are held tightly to the atom
• these materials are insulators• examples:
• wood, ceramics, plastics
• In some materials, electrons are held loosely to the atom are free to move around
• these materials are conductors• examples:
• copper, silver, aluminum
ProtonsAnd
Neutorns
Electrons
Electricity is about how electrons flows through materials
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Fundamentals of ElectricityFundamentals of Electricity
Controlling the flow of electrons is the
foundation for the operation of – Radios
– Ipods
– Computers
– Telephones
– Recorders
– Stereos
– House lights
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Fundamentals of ElectricityFundamentals of Electricity
• There are three characteristics to electricity:– Electromotive Force– Current– Resistance
• All three must be present for electrons to flow
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Fundamentals of ElectricityFundamentals of Electricity
Electromotive Force (EMF or E)– “electro”: electrons– “motive”: movement– “force”: the push
• Electromotive force is the push that causes electrons to move through a conductor
• Measured in volts
• Usually referred to as voltage
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Fundamentals of ElectricityFundamentals of Electricity
Current (I)
• Current is the amount of electrons that flow through a conductor over time
• Measured in amperes – i.e., amps
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Fundamentals of ElectricityFundamentals of Electricity
Resistance (R)
• A material's opposition to the flow of electric current; measured in ohms.
• Measured in ohms
• All materials, even very good conductors have some resistance
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Fundamentals of ElectricityFundamentals of Electricity
• Electrons are confined to conductors, i.e., wires
• Electrons flow only through a closed circuit
– Similar to the flow of water in the pipes of a closed hot water
heating system
– Like a pump that provides the force to push water through
the pipe, a battery provides the electrical push, i.e., voltage,
to push electrons through the wire
![Page 9: Fundamentals of Electricity Franklin County Amateur Radio Club Technician Class License Course Class 3 – Fundamentals of Electricity Bob Solosko W1SRB](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e395503460f94b2ab8c/html5/thumbnails/9.jpg)
Fundamentals of ElectricityFundamentals of Electricity
• Electrons are confined to conductors, i.e., wires
• Electrons flow only through a closed circuit
Closed circuit, current flows Open circuit, no current flows
switch switch
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Fundamentals of ElectricityFundamentals of Electricity
• Electrical circuits
switch
battery
Resistance(resistor)
voltage
current
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Fundamentals of ElectricityFundamentals of Electricity
Relationship between Voltage (E), Current (I) and Resistance (R)
• It takes a certain force (i.e., voltage) to get a certain amount of current (amps) to flow against a specific reststance (ohms)
• A greater resistance requires a greater force (i.e., higher voltage) to get the same amount of current to flow
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Fundamentals of ElectricityFundamentals of Electricity
Relationship between Voltage (E), Current (I) and Resistance (R)
Ohm’s Law
Voltage = Current x Resistance
E = I x RVolts = amps x ohms
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Fundamentals of ElectricityFundamentals of Electricity
Relationship between Voltage (E), Current (I) and Resistance (R)
Ohm’s Law
Current = Voltage/ResistanceI = E / R
Resistance = Voltage/CurrentR = E / I
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Fundamentals of ElectricityFundamentals of Electricity
Ohm’s Law - Summary
• E is voltage– Units - volts
• I is current– Units - amperes
• R is resistance– Units - ohms
• R = E/I• I = E/R• E = I x R
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Fundamentals of ElectricityFundamentals of Electricity
battery
Resistancevoltage
current
10 V5 Ω
2 A
• Electrical circuits – Ohms law
E = I x RI = E / RR = E / I
If voltage V = 10 volts (10 V) and resistance R = 5 ohm (1 Ω)
Then current I = E / R = 10 / 5 = 2 amps (2 A)
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Fundamentals of ElectricityFundamentals of Electricity
• Electrical circuits – Ohms law
E = I x RI = E / RR = E / I
If voltage V = 10 volts (10 V) and resistance R = 5 ohm (1 Ω)
Then current I = E / R = 10 / 5 = 2 amps (2 A)
If voltage = 10 V and current = 20 A
Then resistance R = E / I = 10 / 20 = ½ Ω
battery
Resistancevoltage
current
10 V1/2 Ω
20 A
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Fundamentals of ElectricityFundamentals of Electricity
• Electrical circuits – Ohms law
E = I x RI = E / RR = E / I
If voltage V = 10 volts (10 V) and resistance R = 5 ohm (1 Ω)
Then current I = E / R = 10 / 5 = 2 amps (2 A)
If voltage = 10 V and current = 20 A
Then resistance R = E / I = 10 / 20 = ½ Ω
If resistance = 100 Ω and current = 3 A
Then voltage V = I x R = 3 x 100 = 300 V
battery
Resistancevoltage
current
300 V100 Ω
3 A
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Fundamentals of ElectricityFundamentals of Electricity
• Electrical circuits – Ohms law
battery
Resistancevoltage
current
300 V100 Ω
3 A
![Page 19: Fundamentals of Electricity Franklin County Amateur Radio Club Technician Class License Course Class 3 – Fundamentals of Electricity Bob Solosko W1SRB](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e395503460f94b2ab8c/html5/thumbnails/19.jpg)
Fundamentals of ElectricityFundamentals of Electricity
• Electrical circuits – Ohms law
battery
Resistancevoltage
current
300 V100 Ω
3 A300 V 300 V
The voltage across the resistor is the same as the voltage across the battery
![Page 20: Fundamentals of Electricity Franklin County Amateur Radio Club Technician Class License Course Class 3 – Fundamentals of Electricity Bob Solosko W1SRB](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e395503460f94b2ab8c/html5/thumbnails/20.jpg)
Fundamentals of ElectricityFundamentals of Electricity
• Electrical circuits – Ohms law
battery
Resistancevoltage
current
300 V100 Ω
3 A
![Page 21: Fundamentals of Electricity Franklin County Amateur Radio Club Technician Class License Course Class 3 – Fundamentals of Electricity Bob Solosko W1SRB](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e395503460f94b2ab8c/html5/thumbnails/21.jpg)
Fundamentals of ElectricityFundamentals of Electricity
• Electrical circuits – Ohms law
battery
Resistancevoltage
current
300 V100 Ω
3 A
3 A
3 A
The current is the same anywhere in the circuit
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Fundamentals of ElectricityFundamentals of Electricity
Power
• Moving electrons do work and expend energy:
– generate heat
– generate light
– run motors
– generate and receive radio signals
– compute
• Power is the rate at which electrical energy is generated or consumer
– measured in the units of Watts
• Power = voltage x current P = E x I
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Fundamentals of ElectricityFundamentals of Electricity
Power• Power = voltage x current
P = E x II = P/EE = P/I
• Example 1: 60 watt light bulb– E = 120v, P = 60w, I = ?, R = ?
120 V I
60w bulb
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Fundamentals of ElectricityFundamentals of Electricity
Power• Power = voltage x current
P = E x II = P/EE = P/I
• Example 1: 60 watt light bulb– E = 120v, P = 60w, I = ?, R = ?
I = P/E = 60/120 = ½ AR = E/I = 120/½ = 240Ω
120 V I
battery
Resistancevoltage
current
300 V100 Ω
60w bulb
• Example 2: – E = 300v, R = 100Ω, I = ?, P = ?
I = E/R = 300/100 = 3AP = E x I = 300/3 = 300w
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Fundamentals of ElectricityFundamentals of Electricity
Types of Current
• When current flows in only one direction, it is called direct current (DC).– batteries are a common source of DC.– most electronic devices are powered by DC.
• When current flows alternatively in one direction then in the opposite direction, it is called alternating current (AC).– your household current is AC.– radio waves are AC
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Fundamentals of ElectricityFundamentals of Electricity
Electrical Circuits
• Series circuit – one and only one path for current flow
• Parallel circuit– alternative paths for current flow
battery
Resistor orother component
current
Resistor orother component
battery
Resistor orother component
current
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Fundamentals of ElectricityFundamentals of Electricity
Components: the resistor
• restricts (limits) the flow of current through it
• unit of resistance: ohm (Ω)
• (also dissipates energy as heat)– incadescent lightbulbs– electric stoves
• Circuit Symbol
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Fundamentals of ElectricityFundamentals of Electricity
Components: the resistor
• restricts (limits) the flow of current through it
• unit of resistance: ohm (Ω)
• (also dissipates energy as heat)– incadescent lightbulbs– electric stoves
• A resistor for which the resistance can be changed is a variable resistor or potentiometer
• Circuit Symbol
variableresistor
potentiometer
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Fundamentals of ElectricityFundamentals of Electricity
Components: the resistor
• restricts (limits) the flow of current through it
• unit of resistance: ohm (Ω)
• (also dissipates energy as heat)– incadescent lightbulbs– electric stoves
• A resistor for which the resistance can be changed is a variable resistor or potentiometer
• Circuit Symbol
![Page 30: Fundamentals of Electricity Franklin County Amateur Radio Club Technician Class License Course Class 3 – Fundamentals of Electricity Bob Solosko W1SRB](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e395503460f94b2ab8c/html5/thumbnails/30.jpg)
Fundamentals of ElectricityFundamentals of Electricity
Components: the battery
• source of DC voltage
• stores energy
• provides energy to a circuit
• Circuit Symbol
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Fundamentals of ElectricityFundamentals of Electricity
• temporarily stores electrons and electric current– stores energy in an
electrostatic field
• Unit of capacitance: farad
• composed of parallel metal plates with a non-conductive material (dielectric) in between– dielectric can be air, plastic,
glass, etc.
• A capacitor for which the capacitance can be changed is a variable capacitor
Components: the capacitor• Circuit Symbol
![Page 32: Fundamentals of Electricity Franklin County Amateur Radio Club Technician Class License Course Class 3 – Fundamentals of Electricity Bob Solosko W1SRB](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e395503460f94b2ab8c/html5/thumbnails/32.jpg)
Fundamentals of ElectricityFundamentals of Electricity
• Unit of capacitance: farad– a coulomb is a unit of electrical charge– 1 coulomb = 6,250,000,000,000,000,000 electrons– 1 farad is 1 coulomb/volt
Components: the capacitor
switch
![Page 33: Fundamentals of Electricity Franklin County Amateur Radio Club Technician Class License Course Class 3 – Fundamentals of Electricity Bob Solosko W1SRB](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e395503460f94b2ab8c/html5/thumbnails/33.jpg)
Fundamentals of ElectricityFundamentals of Electricity
• Unit of capacitance: farad– a coulomb is a unit of electrical charge– 1 coulomb = 6,250,000,000,000,000,000 electrons– 1 farad is 1 coulomb/volt
Components: the capacitor
switch
![Page 34: Fundamentals of Electricity Franklin County Amateur Radio Club Technician Class License Course Class 3 – Fundamentals of Electricity Bob Solosko W1SRB](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e395503460f94b2ab8c/html5/thumbnails/34.jpg)
Fundamentals of ElectricityFundamentals of Electricity
• Unit of capacitance: farad– a coulomb is a unit of electrical charge– 1 coulomb = 6,250,000,000,000,000,000 electrons– 1 farad is 1 coulomb/volt
Components: the capacitor
switch
![Page 35: Fundamentals of Electricity Franklin County Amateur Radio Club Technician Class License Course Class 3 – Fundamentals of Electricity Bob Solosko W1SRB](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e395503460f94b2ab8c/html5/thumbnails/35.jpg)
Fundamentals of ElectricityFundamentals of Electricity
• Unit of capacitance: farad– a coulomb is a unit of electrical charge– 1 coulomb = 6,250,000,000,000,000,000 electrons– 1 farad is 1 coulomb/volt
Components: the capacitor
switch
![Page 36: Fundamentals of Electricity Franklin County Amateur Radio Club Technician Class License Course Class 3 – Fundamentals of Electricity Bob Solosko W1SRB](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e395503460f94b2ab8c/html5/thumbnails/36.jpg)
Fundamentals of ElectricityFundamentals of Electricity
• Unit of capacitance: farad– a coulomb is a unit of electrical charge– 1 coulomb = 6,250,000,000,000,000,000 electrons– 1 farad is 1 coulomb/volt
Components: the capacitor
switch
Note: once the capacitor is charged, no more current flows, and the capacitor acts like an open circuit (an open switch)
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Fundamentals of ElectricityFundamentals of Electricity
• Unit of capacitance: farad– a coulomb is a unit of electrical charge– 1 coulomb = 6,250,000,000,000,000,000 electrons– 1 farad is 1 coulomb/volt
Components: the capacitor
switch
![Page 38: Fundamentals of Electricity Franklin County Amateur Radio Club Technician Class License Course Class 3 – Fundamentals of Electricity Bob Solosko W1SRB](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e395503460f94b2ab8c/html5/thumbnails/38.jpg)
Fundamentals of ElectricityFundamentals of Electricity
• Unit of capacitance: farad– a coulomb is a unit of electrical charge– 1 coulomb = 6,250,000,000,000,000,000 electrons– 1 farad is 1 coulomb/volt
Components: the capacitor
switch
![Page 39: Fundamentals of Electricity Franklin County Amateur Radio Club Technician Class License Course Class 3 – Fundamentals of Electricity Bob Solosko W1SRB](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e395503460f94b2ab8c/html5/thumbnails/39.jpg)
Fundamentals of ElectricityFundamentals of Electricity
• Unit of capacitance: farad– a coulomb is a unit of electrical charge– 1 coulomb = 6,250,000,000,000,000,000 electrons– 1 farad is 1 coulomb/volt
Components: the capacitor
switch
![Page 40: Fundamentals of Electricity Franklin County Amateur Radio Club Technician Class License Course Class 3 – Fundamentals of Electricity Bob Solosko W1SRB](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e395503460f94b2ab8c/html5/thumbnails/40.jpg)
Fundamentals of ElectricityFundamentals of Electricity
• Unit of capacitance: farad– a coulomb is a unit of electrical charge– 1 coulomb = 6,250,000,000,000,000,000 electrons– 1 farad is 1 coulomb/volt
Components: the capacitor
switch
![Page 41: Fundamentals of Electricity Franklin County Amateur Radio Club Technician Class License Course Class 3 – Fundamentals of Electricity Bob Solosko W1SRB](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e395503460f94b2ab8c/html5/thumbnails/41.jpg)
Fundamentals of ElectricityFundamentals of Electricity
• Unit of capacitance: farad– a coulomb is a unit of electrical charge– 1 coulomb = 6,250,000,000,000,000,000 electrons– 1 farad is 1 coulomb/volt
Components: the capacitor
switch
~AC voltage
![Page 42: Fundamentals of Electricity Franklin County Amateur Radio Club Technician Class License Course Class 3 – Fundamentals of Electricity Bob Solosko W1SRB](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e395503460f94b2ab8c/html5/thumbnails/42.jpg)
Fundamentals of ElectricityFundamentals of Electricity
• Unit of capacitance: farad– a coulomb is a unit of electrical charge– 1 coulomb = 6,250,000,000,000,000,000 electrons– 1 farad is 1 coulomb/volt
Components: the capacitor
switch
~AC voltage
Note: a capacitor allows AC current to flow
![Page 43: Fundamentals of Electricity Franklin County Amateur Radio Club Technician Class License Course Class 3 – Fundamentals of Electricity Bob Solosko W1SRB](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e395503460f94b2ab8c/html5/thumbnails/43.jpg)
Fundamentals of ElectricityFundamentals of Electricity
• Capacitive reactance (XC)
– the opposition to alternating current due to capacitance
– unit of capacitive reactance: ohms
– is inversely proportional to the signal frequency and the
capacitance
– XC = - 1 / (2fC)
• Note: if f = 0, i.e. DC current, XC = ∞, i.e., an open circuit
Components: the capacitor
![Page 44: Fundamentals of Electricity Franklin County Amateur Radio Club Technician Class License Course Class 3 – Fundamentals of Electricity Bob Solosko W1SRB](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e395503460f94b2ab8c/html5/thumbnails/44.jpg)
Fundamentals of ElectricityFundamentals of Electricity
• stores electric current– stores energy in a magnetic
field– any wire with a current
flowing through it creates a magnetic field
• unit of inductance: henry
• magnetic field is strengthened by coiling wire, i.e., inductance is increases
• an inductor for which the inductance can be changed is a variable inductance
• An inductor may have an iron core to increase the inductance
• Circuit Symbol
Components: the inductor
![Page 45: Fundamentals of Electricity Franklin County Amateur Radio Club Technician Class License Course Class 3 – Fundamentals of Electricity Bob Solosko W1SRB](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e395503460f94b2ab8c/html5/thumbnails/45.jpg)
Fundamentals of ElectricityFundamentals of Electricity
• Inductive reactance (XL)
– the opposition to alternating current due to inductance
– unit of inductance reactance: ohms
– is proportional to the signal frequency and the inductance
– XL = + 2fL
• Note: if f = 0, i.e. DC current, XL = 0, i.e., an short circuit
Components: the inductor
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Fundamentals of ElectricityFundamentals of Electricity
• Impedance is the total opposition to alternating current due to
reistance, capacitance and inductance
– unit of impedance: ohms
– Z = √ R2 + (XC + XL)2
• Resonance:
When XC = XL,
Then Z = R
Impedance (Z):
~AC voltage
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Fundamentals of ElectricityFundamentals of Electricity
• controls the flow of current– like an electronically controlled
valve.
– like the faucet in your sink
• used to amplify a signal or as an on-off switch
– A small current or voltage on the “base (B)” lead causes a large change in the current flowing between the “emitter (E)” and “collector (C)” leads
• Circuit Symbol
Components: the transistor
B
E
C
![Page 48: Fundamentals of Electricity Franklin County Amateur Radio Club Technician Class License Course Class 3 – Fundamentals of Electricity Bob Solosko W1SRB](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e395503460f94b2ab8c/html5/thumbnails/48.jpg)
Fundamentals of ElectricityFundamentals of Electricity
• controls the flow of current– like an electronically controlled
valve.
– like the faucet in your sink
• used to amplify a signal or as an on-off switch
– A small current or voltage on the “base (B)” lead causes a large change in the current flowing between the “emitter (E)” and “collector (C)” leads
• Circuit Symbol
Components: the transistor
B
E
C
![Page 49: Fundamentals of Electricity Franklin County Amateur Radio Club Technician Class License Course Class 3 – Fundamentals of Electricity Bob Solosko W1SRB](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e395503460f94b2ab8c/html5/thumbnails/49.jpg)
Fundamentals of ElectricityFundamentals of Electricity
• controls the flow of current– like an electronically controlled
valve.
– like the faucet in your sink
• used to amplify a signal or as an on-off switch
– A small current or voltage on the “base (B)” lead causes a large change in the current flowing between the “emitter (E)” and “collector (C)” leads
• Circuit Symbol
Components: the transistor
B
E
C
![Page 50: Fundamentals of Electricity Franklin County Amateur Radio Club Technician Class License Course Class 3 – Fundamentals of Electricity Bob Solosko W1SRB](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e395503460f94b2ab8c/html5/thumbnails/50.jpg)
Fundamentals of ElectricityFundamentals of Electricity
• controls the flow of current– like an electronically controlled
valve.
– like the faucet in your sink
• used to amplify a signal or as an on-off switch
– A small current or voltage on the “base (B)” lead causes a large change in the current flowing between the “emitter (E)” and “collector (C)” leads
• Circuit Symbol
Components: the transistor
![Page 51: Fundamentals of Electricity Franklin County Amateur Radio Club Technician Class License Course Class 3 – Fundamentals of Electricity Bob Solosko W1SRB](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e395503460f94b2ab8c/html5/thumbnails/51.jpg)
Fundamentals of ElectricityFundamentals of Electricity
• a collection of components contained in one device – replaces many individual
components
– a “black-box” for a specific function
– examples:• amplifier• switch• voltage regulator• mixer• display controller
Components: the integrated circuit
• Circuit Symbol
![Page 52: Fundamentals of Electricity Franklin County Amateur Radio Club Technician Class License Course Class 3 – Fundamentals of Electricity Bob Solosko W1SRB](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e395503460f94b2ab8c/html5/thumbnails/52.jpg)
Fundamentals of ElectricityFundamentals of Electricity
• Allows current to flow in only one direction
• Circuit SymbolComponents: diode
• interrupts the flow of current if the current exceeds some value
– Fuses blow – one time protection.
– Circuit breakers trip – can be reset and reused.
• Circuit Symbol
Components: fuses and circuit breakers
• Special type of diode that emits light when current passes through it
Components: light emiting diode (LED)
![Page 53: Fundamentals of Electricity Franklin County Amateur Radio Club Technician Class License Course Class 3 – Fundamentals of Electricity Bob Solosko W1SRB](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e395503460f94b2ab8c/html5/thumbnails/53.jpg)
Fundamentals of ElectricityFundamentals of Electricity
Other Circuit Symbols:
![Page 54: Fundamentals of Electricity Franklin County Amateur Radio Club Technician Class License Course Class 3 – Fundamentals of Electricity Bob Solosko W1SRB](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e395503460f94b2ab8c/html5/thumbnails/54.jpg)
Fundamentals of ElectricityFundamentals of Electricity
Circuit Diagrams: examples
Amplifier
![Page 55: Fundamentals of Electricity Franklin County Amateur Radio Club Technician Class License Course Class 3 – Fundamentals of Electricity Bob Solosko W1SRB](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e395503460f94b2ab8c/html5/thumbnails/55.jpg)
Fundamentals of ElectricityFundamentals of Electricity
Light control Antenna tuner
Power supply – converts 120VAC to DC
![Page 56: Fundamentals of Electricity Franklin County Amateur Radio Club Technician Class License Course Class 3 – Fundamentals of Electricity Bob Solosko W1SRB](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e395503460f94b2ab8c/html5/thumbnails/56.jpg)
Fundamentals of ElectricityFundamentals of Electricity
• resistor values may be ohms (Ω), kilo ohms (kΩ) or mega ohms (MΩ)
• capacitor values typically are microfarads (μf) or pico farads (pf)
• inductance values are typically milli henrys (mh) or micro henrys (μh)
• frequencies are typically kilo hertz (kHz) or mega Hertz (MHz)
• voltage is often volts (V) milli volts (mV) or micro volts (μV)
• current is often amps (A), milli amps (mA) or micro amps (μA)
Very Large and Very Small Numeric Values: Units
![Page 57: Fundamentals of Electricity Franklin County Amateur Radio Club Technician Class License Course Class 3 – Fundamentals of Electricity Bob Solosko W1SRB](https://reader030.vdocuments.us/reader030/viewer/2022032803/56649e395503460f94b2ab8c/html5/thumbnails/57.jpg)
Fundamentals of ElectricityFundamentals of Electricity
• decibels are used to compare values that vary over a very large range
– signal levels, amplifier gain, sound levels
• decibles compare values on a logrithmic scale
• 3 dB is a factor of 2
– a 3 dB gain in an amplifier means that the output level is twice the input level
• 10 dB is a factor of 10
– a 10 dB gain in an amplifier means that the output level is 10 times the input level
• decibels add:
– 3 dB = 2 times
– 6 dB = 2 x 2 = 4 times
– 9 dB = 2 x 2 x 2 = 8 times
– 12 dB = 2 x 2 x 2 x 2 = 16 times
– 10 dB = 10 times
– 20 dB = 10 x 10 = 100 times
– 30 dB = 10 x 10 x 10 = 1000 times
Very Large and Very Small Numeric Values: decibels (dB)