ITEC 220 Test #1 Flashcards
Short circuit
An unintended path for current to flow which bypasses the intended devices
A three-wire line cord has one connector tied to chassis ground
True
Fuse
A protection device which overcurrent produces heat to melt a fusible element
Circuit breaker
A circuit interruption device that activates when an overcurrent is applied
Thermal overload
A protection device that opens when the ambient temperature rises above the rated value
Electromechanical relay
A switch that is activated by electromagnetism
If a fuse blows, replace it with a higher valued one
False
A fuse is what type of indicator
Circuit overload
An interlock or third-wire ground plug is an example of
Prevention protection
Schematic symbol
Drawings that represent components
Transducer
A device that changes one from of energy into another form
Atom
The smallest particle of an element
Proton
A heavy positive particle in the nucleus of an atom
Electron
A light negative particle orbiting the nucleus of an atom
Nucleus
The center of an atom. It consists of protons and neutrons
Neutron
A heavy particle, having no charge, found in the nucleus of an atom
Charge
The attraction and repulsion between particles
Element
A material that cannot be broken down by chemical reaction
Molecule
The smallest unit of a compound that has the same characteristics as the compound
Compound
A material whose molecules are the same
Shells/rings
The layers in which the electrons are found
The smallest particles into which an atom can be divided are called
Protons and electrons
An electron has a negative charge
True
Unlike charges repel each other
False
What is formed when two or more atoms of different elements are combined
A molecule
Valence electrons
The outermost electrons of an atom
Free electrons
Valence electrons that can move easily from atom to atom
Insulators
Compounds in which the bonding of the atoms prevent the valence electrons from becoming free electrons
Dielectrics
Insulators that help electrodes store charge
Conductor
Material whose atoms on the outer ring are less than half complete
Semiconductor
Element whose outer ring is half of electrons is exactly half complete
Resistance
The opposition to the movement of electrons in a conductive material
Ohm
The unit of electrical resistance (a current of 1 amp will flow when there is a potential difference of 1 volt across it.)
Mil
One-thousandth of an inch
Circular mils
Equal the square of the diameter expressed in mils
How many electrons are in the outer ring of atoms of semiconductor material
4 electrons
A conductor has (few,many) free electrons
Few
Static electricity
Refers to the electrical charge generated by friction
Coulomb
A unit of charge equal to the charge produced by 6.24 x 10 to the eighteenth
Potential difference
Difference between points A and B is the potential of B subtracted by A.
Volt
A unit of potential difference (can move 1 coulomb of charge while producing 1 unit of electrical work)
Joule
The unit of work energy
Electromotive force
The potential difference between the terminals of a device which can be a source of electrical energy
Current
The movement of electrical charge
Ampere
The unit of current
Conductance
The ability of a circuit to move electrical charges
Watt
The expenditure of one joule of energy in one second of time
What is the basic unit used to describe a difference of potential
Volt
Current defines a quantity of flow of electrons
True
Electrode
Electrical conductor by which current enters or leaves a medium such as an electrolyte.
Electrolyte
Any solution that conducts electric current
Anode
The negative terminal of a primary cell. The terminal where oxidation takes place
Cathode
The positive terminal of a primary cell
Battery
A voltage source which is usually a combination of electrochemical cells
Wet cell
Cell that has liquid electrolytes
Dry cell
Cell having the electrolyte in the form of a moist paste
Primary cell
A cell that converts chemical energy to electrical energy by an irreversible chemical reaction
Secondary cell
A cell that converts chemical energy into electrical energy, but the cell can be recharged
Five methods of generating voltage
Mechanical, chemical, static, thermal, and light
Why is a voltaic cell impractical to use
Because the charges have reached a state of equilibrium
What method of generating electricity is most widely used for home lighting and appliances
Mechanical
Piezoelectric effect
An effect in which electric polarization is produced by mechanical pressure
Thermocouple
A device consisting of two metals, one whose junction is kept at a fixed temp
What determines the amount of voltage generated by a solar cell
The intensity of the sun
What could a solar cell be used for
Satellites
What determines the amount of current generated by a thermocouple
Intensity of the heat applied
Possible applications of a thermocouple
Temperature control and monitoring inudstrial processes
What is piezoelectricity
Mechanical pressure of crystals that create an electrical charge
Resistor
Components designed to have specific numbers of ohms of resistance
