CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as...
-
Upload
kerry-page -
Category
Documents
-
view
223 -
download
0
Transcript of CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as...
![Page 1: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/1.jpg)
CVT 102
![Page 2: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/2.jpg)
Electron Theory
◦ All electronic effects caused by movement of electrons
◦ Serves as basis for design of electrical equipment
![Page 3: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/3.jpg)
![Page 4: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/4.jpg)
Composed of protons, electrons, neutrons◦ Nucleus
positively charged protons neutral neutrons
Negative charged electrons travel in orbits around nucleus
![Page 5: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/5.jpg)
Atomic Number◦ Number of protons in the nucleus◦ Determines characteristics of atom
Mass Number◦ Number of protons and neutrons in the nucleus◦ On periodic table, given as average of commonly
occurring isotopes
![Page 6: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/6.jpg)
Electrons ◦ Revolve in shells or orbits◦ Close to nucleus — strong attraction; outer orbits
— less attracted◦ Free electrons located in outer orbits; movement
creates electric current
![Page 7: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/7.jpg)
Electron Theory◦ All electronic effects caused by movement of
electrons◦ Serves as basis for design of electrical equipment
Atoms, Electrons, Matter◦ Matter has mass and occupies space; consists of
atoms
![Page 8: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/8.jpg)
Atoms, Electrons, Matter◦Atoms
Composed of protons, electrons, neutrons
Nucleus is center; contains positive charged protons and neutral charged neutrons
Negative charged electrons travel in orbits around nucleus
Atoms held together by opposite charges of protons and electrons
Different elements have varying numbers of protons and electrons
![Page 9: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/9.jpg)
Atoms, Electrons, Matter◦ Electrons
Revolve in shells or orbits Close to nucleus – strong attraction; outer orbits –
less attracted Free electrons located in outer orbits; movement
creates electric current Electricity: term actually describes movement of free
electrons moving from orbit of one atom to another (principle based on Bohr’s Theory)
![Page 10: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/10.jpg)
Atoms, Electrons, Matter◦ Electrons con’t.
A conductor is a material that allows flow of free electrons
The greater the number of electrons in a substance, the better the conductor
Copper is the most commonly used material for a conductor. Silver, zinc and brass are also used.
Devices in O.R. that use copper as a conductor: surgical lamps, ESU, power drills
Water is a conductor; humidity in O.R. should be maintained at 50%-60%
![Page 11: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/11.jpg)
Insulators◦ Materials with small number of free electrons;
inhibit flow of electrons◦ Basically poor conductors◦ Used to wrap conductors to preserve current and
prevent leakage of electrons◦ Types of insulators
Rubber cord, plastic around ESU or X-ray machine
![Page 12: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/12.jpg)
Electrical Charge◦ Can be either positive or negative◦ Defined as too many or too few electrons orbiting
an atom◦ Law of Electric Charge: like charges repel each
other; unlike charges attract each other; opposites attract
![Page 13: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/13.jpg)
Electrical Current◦ Movement of electrical charge◦ Current moves through conductors by movement
of free electrons migrating from atom to atom inside conductor
![Page 14: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/14.jpg)
Magnetic Fields◦ Electrons create a magnetic field or electric
charge while orbiting the nucleus In some materials electrons travel in the same
direction, combining magnetic fields Natural magnetic substances include iron, nickel,
cobalt, even the earth◦ Electrical generators depend on the close
relationship of electricity and magnetism
![Page 15: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/15.jpg)
Magnetic Fields con’t.◦ Earth
Two poles, north and south Magnetic field is lines of magnetic force between
poles Magnetic field causes metal objects to be attracted
to the magnet; needle in a compass
![Page 16: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/16.jpg)
Electromagnets◦ Metals that become magnetic when encircled by a
conductor◦ Magnetic field created by current traveling
through conductor◦ Magnetic field used to create electricity
Electricity does not create power; only means for transporting it
◦ Interaction between wires and magnets produces power
![Page 17: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/17.jpg)
Electromagnets con’t.◦ Example: Power plant
Water from dam heated forms steam turns turbines (generators) turbines spin magnets electricity is created for use
![Page 18: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/18.jpg)
Terminology Volt is electrical potential
– Voltage is potential energy of electrons
– Named after Alessandro Volta, a 17th century scientist who invented the battery
Electric system: battery creates voltage to move electricity
Circuit is the path electricity travels
![Page 19: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/19.jpg)
Measured in amperes (amps) Rate of flow of electrons Current flow is the movement of free
electrons Free electrons attracted from point of
excess electrons to a point with fewer electrons
![Page 20: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/20.jpg)
Scientific law of electricity – Mathematical equation showing how voltage,
current, and resistance interrelate – Ohm’s Law: V = I x R
Resistance◦ Restricting flow of current; measured in ohms
Ohm’s Law – More voltage will increase current if resistance
is constant; higher resistance causes decreased current if voltage is constant
![Page 21: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/21.jpg)
Rate at which work is completed◦ Rate of movement of electrons or current flow◦ Product of voltage & current is power◦ P = I x V
Measured in watts (W)◦ Converted to kilowatts (KW): 1 KW = 1,000 W◦ Example: DC Circuit is 12V & 20A, Power is
P = 20 x 12 = 240W or 0.24KW
![Page 22: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/22.jpg)
Device that uses electricity to perform a function
Can change amount of energy from power source
Examples: surgical lamps, ESU, power drills, video monitors
Resistive energy loads: conductor has high resistance to flow of electricity◦ Example: filament (conductor) in light bulb;
electricity has to force way thru resistance to cause filament to glow
![Page 23: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/23.jpg)
Device used to open or close circuit◦ Controls flow of electricity
Example: Flashlight◦ Batteries (power)◦ Wires (conductors) connected to battery that is
connected to switch activated by user◦ Bulb (load) must have voltage◦ Voltage carried by conductors and switch controls
flow of current to load; open switch – no flow, closed switch bulb lights up
![Page 24: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/24.jpg)
Hot Wire◦ Wire that connects to switch; colored red
Neutral Wire◦ Pathway for electrons to return to energy source;
complete the circuit; colored green Ground Wire
◦ Sends leaking electrons to ground to prevent shock; colored black
![Page 25: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/25.jpg)
Devices made of materials that are purposely resistive
Designated with letter R
![Page 26: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/26.jpg)
Electrical current flows in one direction – negative to positive pole
Example: Batteries◦ Serve as storage device; keep electricity until
needed◦ Negative (-) and positive (+) terminals◦ When switch is closed, current flows from one
terminal to the other
![Page 27: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/27.jpg)
Batteries con’t.◦ Four components of DC circuit
Battery: source of electricity Wire (battery to load): conductor Switch: control device Load: bulb
![Page 28: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/28.jpg)
Current that periodically reverses direction Complete cycle is current that moves in one
direction, then reverses direction Hertz (Hz): one AC cycle Frequency: number of AC cycles in a
second; symbol ƒ Most common AC in U.S. is 60 cycle AC Typical voltage is 110V or 120V
![Page 29: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/29.jpg)
AC Can Change Voltage◦ AC delivered as high voltage, then “stepped
down”◦ Example:
Transformers “step up” exiting voltage Power lines (transformer) deliver electricity at high
voltage Voltage is stepped down before use
![Page 30: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/30.jpg)
Frequency is number of wave cycles (one cycle is a hertz) per second
Radio and TV signals are electromagnetic waves◦ Radio transmitter delivers signal to antennae
system◦ Electromagnetic signals travel through cable, air
or optical fiber to receiving antennae◦ RF spectrum begins at 9 kHz (or less) to over 3
GHz
![Page 31: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/31.jpg)
Cause of electrical shock Secondary circuit contains hazardous
current due to isolated circuit◦ Transformer insulation isolates secondary circuit◦ Person touches both poles of non-insulated
isolated circuit and experiences an electrical shock and/or burn
![Page 32: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/32.jpg)
Secondary Circuit con’t.◦ Two methods of prevention:
Solid insulation placed as total barrier to prevent complete access to circuit
Conductive barrier of insulation between isolated circuit and conductive barrier
![Page 33: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/33.jpg)
Application of electrical current through tissue to coagulate bleeding or cut tissue
Electrosurgical Unit (ESU): Device that provides power for electric current
Electrosurgery: Electrical currents applied directly to tissue; utilizes AC current
Electrocautery: Uses heated wire to burn tissue; no electricity enters body; utilizes DC current
![Page 34: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/34.jpg)
ESU Circuit: Current Flow◦ Generator thru conductor cord active
electrode (Bovie tip) surgical site (energy converted to thermal energy to cut or coagulate) thru patient dispersive electrode (grounding pad) conductor cord generator
![Page 35: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/35.jpg)
Used for delicate procedures, presence of moisture, prevent nerve damage
Two prongs of forceps: active and inactive electrodes◦ Current travels through one tip, passes thru
tissue, disperses to other tip No dispersive electrode required
![Page 36: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/36.jpg)
Flow of current is as described in Slide 35 Dispersive Electrode (grounding pad)
◦ Placement is critical to avoid electrical burns to patient
◦ Pad must be in complete contact with patient’s skin
◦ Pad pulled up or portion not in contact, may result in second or third degree burns to patient
![Page 37: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/37.jpg)
Shock and Burn◦ Patient
Burns usually deep; tissue necrosis; thrombosis Debridement
◦ Sterile Surgery Team Members RF Capacitive Coupling: AC travels from active
electrode, through intact insulation, burns skin; apply active electrode beneath Crile held by surgeon to prevent burns
![Page 38: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/38.jpg)
Shock & Burn con’t.◦ Sterile Surgery Team Members
Dielectric Breakdown: High voltage breaks down insulating material, such as sterile glove; produces hole in glove – surgical team member sustains small burn
![Page 39: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/39.jpg)
Vaporized Tissue Plume◦ Occurs during procedures involving
electrosurgery, lasers, power drills◦ Plume is vaporized tissue◦ Contains hazardous bioparticles that are
carcinogenic, mutagenic, and they may carriy bloodborne pathogens
◦ Surgical technologists utilize suction to “suck smoke” from wound when using electrosurgery or smoke evacuators for lasers
![Page 40: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/40.jpg)
Electricity ◦ Describes movement of free electrons moving
from orbit of one atom to another (principle based on Bohr’s Theory)
![Page 41: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/41.jpg)
Conductor◦ material that allows flow of free electrons◦ Copper is the most commonly used material for a
conductor. Silver, zinc and brass are also used.
![Page 42: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/42.jpg)
Insulators ◦ Materials with small number of free electrons;
inhibit flow of electrons◦ Basically poor conductors◦ Used to wrap conductors to preserve current and
prevent leakage of electrons◦ Types of insulators
Rubber cord, plastic, paper
![Page 43: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/43.jpg)
![Page 44: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/44.jpg)
Electrical Charge◦ Can be either positive or negative◦ Charged is conserved
Neutral objects contain equal numbers of positive and negative charges
◦ Like charges repel; unlike charges attract
![Page 45: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/45.jpg)
The force (attraction or repulsion) between two charged particles is proportional to the product of their charges and inversely proportional to the square of the distance between them. (Inverse square law)
![Page 46: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/46.jpg)
SI unit ◦Coulomb (C) 6.25 X 1018 electrons
Very large amount of charge Coulomb force between two charges of 1 .0
C each separated by 1 .0 m is 9X109 N (about 1 million tons)
![Page 47: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/47.jpg)
Charges on surface of object Charge is greater on curved surface;
greater the curvature, the greater the charge
Click here for more information about static electricity
![Page 48: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/48.jpg)
Electrical Current ◦ Movement of electrical charge◦ Current moves through conductors by movement
of free electrons migrating from atom to atom inside conductor
![Page 49: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/49.jpg)
Magnetic Fields◦ Electrons create a magnetic field or electric
charge while orbiting the nucleus◦ In some materials electrons travel in the same
direction, combining magnetic fields◦ Natural magnetic substances include iron, nickel,
cobalt, even the earth
![Page 50: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/50.jpg)
Magnetic Fields◦ Earth Two poles, north and south Magnetic field is lines of magnetic force
between poles Magnetic field causes metal objects to
be attracted to the magnet; needle in a compass
![Page 51: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/51.jpg)
• Electromagnets◦ Metals that become magnetic when encircled by a
conductor with an electric current◦ Magnetic field created by current traveling
through conductor
![Page 52: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/52.jpg)
Electrical generators depend on the close relationship of electricity and magnetism
Magnetic field used to create electricity◦ Interaction between wires and magnets produces
electricity
![Page 53: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/53.jpg)
Example: Power plant • Water from dam heated —* forms steam —* turns turbines (generators) —* turbines spin magnets —* electricity is created for use
![Page 54: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/54.jpg)
Volts◦ Volt is electrical potential ◦ Voltage is potential energy of electrons ◦ Named after Alessandro Volta, a 17th
century scientist who invented the battery
Electric system: battery creates voltage to move electricity
Circuit is the path electricity travels
![Page 55: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/55.jpg)
Measured in amperes (amps) Rate of flow of electrons Current flow is the movement of free
electrons◦ Free electrons attracted from point of excess
electrons to a point with fewer electrons
![Page 56: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/56.jpg)
Device that uses electricity to perform a function Can change amount of energy from power source
◦ Examples: lights, ESU, power drills, video monitors◦ Resistive energy loads: conductor has high resistance to
flow of electricity Example: filament (conductor) in light bulb; electricity has to
force way thru resistance to cause filament to glow Measured in Ohms (Ώ)
![Page 57: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/57.jpg)
Mathematical equation showing how voltage, current, and resistance interrelate
Ohm’s Law: V=IxR
◦ More voltage will increase current if resistance is constant
◦ Higher resistance causes decreased current if voltage is constant
![Page 58: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/58.jpg)
![Page 59: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/59.jpg)
![Page 60: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/60.jpg)
Rate at which work is completed Rate of movement of electrons or current
flow Product of voltage & current is power
P=IxV
![Page 61: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/61.jpg)
Measured in watts (W) o Converted to kilowatts (KW): 1 KW = 1,000 W o Example: DC Circuit is 12V & 20A,
Power is o P=20x12=24OWorO.24KW
![Page 62: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/62.jpg)
Device used to open or close circuit ◦ Controls flow of electricity
Example: Flashlight Batteries (power) Wires (conductors) connected to battery that is
connected to switch activated by user Bulb (load) must have voltage Voltage carried by conductors and switch controls flow
of current to load open switch — no flow closed switch bulb lights up
![Page 63: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/63.jpg)
Hot Wire ◦ Wire that connects to switch; colored red
Neutral Wire◦ Pathway for electrons to return to energy source;
complete the circuit; colored green Ground Wire
◦ Sends leaking electrons to ground to prevent shock; colored black
![Page 64: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/64.jpg)
Electrical current flows in one direction — negative to positive pole◦ Example: Battery
Serves as storage device; keep electricity until needed
Negative (-) and positive (+) terminals When switch is closed, current flows from one
terminal to the other
![Page 65: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/65.jpg)
Four components of DC circuit ◦ Battery: source of electricity ◦ Wire (battery to load): conductor ◦ Switch: control device ◦ Load: bulb
![Page 66: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/66.jpg)
Current that periodically reverses direction Complete cycle is current that moves in
one direction, then reverses direction◦ Hertz (Hz): one AC cycle◦ Frequency: number of AC cycles in a second;
symbol f ◦ Most common AC in U.S. is 60 cycle AC ◦ Typical voltage is 110V or 120V
![Page 67: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/67.jpg)
AC voltage can be changed by transformer AC delivered as high voltage, then “stepped down” Example
◦ Transformers “step up” exiting voltage ◦ Power lines (transformer) deliver electricity at high voltage ◦ Voltage is stepped down before use
![Page 68: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/68.jpg)
Fuses Circuit breakers Ground
![Page 69: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/69.jpg)
Mutual induction
The transformer equation relates the number of turns of wire to the difference in voltage between the primary and secondary coils.
Vp/Vs = Np/Ns◦ Where Vp is the voltage in the primary coil.
Vs is the voltage in the secondary coil.Np is the number of turns of wire on the primary coil.Ns is the number of turns of wire on the secondary coil.
![Page 70: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/70.jpg)
Step-up transformer
Click on the image above for more information
![Page 71: CVT 102. Electron Theory ◦ All electronic effects caused by movement of electrons ◦ Serves as basis for design of electrical equipment.](https://reader036.fdocuments.in/reader036/viewer/2022062321/56649e395503460f94b2aaa4/html5/thumbnails/71.jpg)
Step-down transformer
Click on the image above for more information