Transcript Chapter 1- Fundamentals of Electricity

Chapter 1
Fundamentals of Electricity
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Matter
Occupies space.
 Has weight.
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Periodic Table
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Elements
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Basic building block of nature.
Cannot be reduced to a simpler
substance by chemical means.
Over 100 known elements.
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Parts of an atom
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Nucleus
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Protons
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Positively charged particles inside nucleus.
Neutrons
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Located at center of atom.
Uncharged particles inside nucleus.
Electrons
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Negatively charged particles that orbit nucleus.
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Atomic number
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The number of protons in the nucleus of
the atom.
Atomic weight
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The mass of an atom.
Determined by the total number of protons
and neutrons in the nucleus.
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Shell
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Valence Shell
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Electrons orbit here.
Concentric circles around nucleus.
Filled in sequence.
The outermost shell.
Valence
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The number of electrons contained in the
valence shell.
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Conductors
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Materials that
contain a large
number of free
electrons.
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Insulators
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Prevent the flow
of electricity.
Stabilized by
absorbing valence
electrons.
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Semiconductors
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Negative Ion
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Can be altered to function as either a
conductor or insulator.
A negatively charged atom.
Positive Ion
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A positively charged atom.
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Ionization
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The process of gaining or losing electrons
Significant in current flow.
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Current
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Movement of electrons from negatively charged
atoms to positively charged atoms.
Represented with the symbol I.
Coulomb
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Unit adopted for measuring electricial charges.
6.24 x 1018 electrons.
Represented with the symbol C.
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Ampere
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One coulomb (charge) moving past a
single point in one second.
Named for French physicist André Marie
Ampère.
Current is measured in amperes.

Represented by the symbol A.
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Potential
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The ability of the source to perform electrical
work.
Difference of Potential
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The actual work accomplished in a circuit is the
result of the “difference in potenial” available
between the two ends of a circuit,
Causes electrons to move or flow in a circuit
Referred to as voltage.
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Voltage
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The force that moves the electrons in the
circuit.
The pressure or pump that moves
electrons.
Represented by the symbol E.
Unit of measure called the volt.
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Resistance
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Opposition to the flow of electrons.
Degree of resistance depends on size,
shape or temperature,
Represented by the symbol R
Measured in Ohms.
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Named for George Simon Ohm
Represented by Greek letter Omega ().
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Conductors
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Low resistance to current flow.
Many free electrons.
Insulators
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High resistance to current flow.
Few free electrons.