Introduction to Electrical Theory Flashcards
NCCR 23103-23, Delmar's Unit 1
What are the three parts of an atom?
Proton. Neutron. Electron.
What is a valence shell?
The outermost ring of electrons in an atom.
A proton has what charge?
Positive
A neutron has what change?
None
An electron has what charge?
Negative
What is an ion?
An atom that gains or loses an electron
What is a conductor?
A material through which it is relatively easy to maintain an electric current.
What is an insulator?
A material through which it is difficult to conduct an electric current.
What is a semiconductor?
A material that has electrical properties between that of a conductor and an insulator.
How many valence electrons does a conductor have?
Three or fewer
How many valence electrons does a semiconductor have?
Four
How many valence electrons does an insulator have?
Five or more
What are some examples of conductors?
Copper and aluminum
What are some examples of semiconductors?
Germanium and silicon
What are some examples of insulators?
Porcelain and plastic
Define voltage
The driving force that makes current flow
What symbol is used for voltage?
E
Define current
The movement, or flow, of electrons in a circuit.
What is the symbol for current?
I
What is current measured in?
Amperes (Amps)
Define resistance
An electrical property that opposes the flow of current through a circuit.
What is the symbol for resistance?
R
What is resistance measured in?
Ohms (Ω)
Define power
The rate of doing work, or the rate at which energy is used or dissipated.
What is electrical power measured in?
Watts
Define coulomb (C)
A unit of electrical charge equal to 6.24 x 10^18 (6,240,000,000,000,000,000) electrons
Define joule (J)
A unit of energy measurement for doing work. One joule is equal to one newton-meter (Nm)
What is conventional current theory?
The electrical theory that electrons flow from positive to negative
What is electron flow theory?
The electrical theory that electrons flow from negative to positive
What factors affect current?
Applied voltage. Wire size. Conductor material. Temperature. Conductor length.
How does conductor length affect resistance?
As the wire length increases, the resistance also increases
How does wire size affect resistance?
The resistance goes down as the wire size goes up
What is ohms law?
Current = Voltage / Resistance (I = E / R)
What is the power equation?
Power = Current * Amperes (P = E * I)
How many watts in a horsepower?
746
Define kilo
1,000
Define mega
1,000,000
Define watt
The basic measurement of electrical power. One watt equals one ampere of current flowing through a potential difference of one volt.
What are the six methods for producing electricity?
Magnetism. Chemical action. Pressure. Heat. Friction. Light.
What is the most common method of producing electricity?
Magnetism
What is the second most common method of producing electricity?
Chemical action
What are the five basic effects that can be caused by electricity?
Magnetism. Chemical reactions. Light. Heat. Pressure.
Define photon
A massless particle of pure energy
How are photons produced?
When electrons move from one energy level to another.
