Science of Electricity and Electronics

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Science of Electricity and Electronics

• Colts Neck High School
• Applied Technology

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The Nature of Matter
ELEMENT
COMPOUND
Mixture of two or more elements.
Pure form of matter.
ATOMS
MOLECULE
Smallest part of an element.
Smallest part of a compound.
Electrons Negative part of atom
Protons Positive part of atom
Neutron No charge or neutral part
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The Atom
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Ionization

• Ionization occurs when an atom loses or gains an
  electron. It is caused by heat, friction, or
  bombardment by electrons.
• Positive Ion an electron leaves the atom,
  leaving the atom positively charged.
• Negative Ion an electron is gained by the atom,
  leaving the atom negatively charged.

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Static Electricity

• Law of Charges
• Like charges repel each other, and unlike charges
  attract each other.
• Electrostatic Field
• The field of force surrounding a charged body.

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Transfer of Electrons

• Conduction
• Transferring electrons by directly touching two
  object together or by connecting them with a
  conductor.
• Induction
• Changing the charge of an object by bringing it
  near a charged object. When an object is charged
  by induction it takes on the opposite charge.

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Application of Static Electricity
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Basic Electric Circuits

• Voltage the force behind electron flow.
• (V) the symbol that represents voltage
• Similar to horsepower in an engine
• Current the flow of electron.
• (A) the symbol that represents ampere
• Similar to the speed of a flowing river
• Resistance the opposition to the flow of
  electrons
• (?) the symbol that represents ohms

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Conductors and Insulators

• Conductors allow for the free flow of
  electrons.
• copper, aluminum, salt water, damp earth
• Insulators prevent the free flow of electrons.
• glass, porcelain, air, sand, paper, oil
• Semi-conductors considered neither a good nor a
  poor conductor.

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Circuits

• Series Circuit electrons have only one path to
  follow.
• Parallel Circuit electrons have multiple paths
  to follow.

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Electron Flow

• Conventional Current Flow (CCF) - Electricity
  flowed from positive to negative. A theory that
  was created over 200 years ago, when scientists
  arbitrarily chose a polarity direction.
• Electron Flow Theory (EFT) A theory which
  states that electrons flow from negative to
  positive, and which is widely accepted as
  correct.
• Many schematic drawings are still drawn in CCF

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Electric Current

• Direct Current
• Current flows in only one direction in an
  electrical circuit.
• Example - Battery
• Alternate Current
• Current flows in both directions in an electrical
  circuit.
• Example Home Outlet

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Ohms Law

• Current measured in amperes (I) in a circuit is
  equal to the applied voltage (E) divided by the
  resistance (R).

E I x R I E / R R E/I
Applied voltage is equal to the current
multiplied by the resistance. Current is equal to
applied voltage divided by the resistance. Resista
nce is equal to the applied voltage divided by
the current.
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Electrical Prefixes

• tera T 10x12
• giga G 10x9
• mega M 10x6
• kilo k 10x3
• basic unit
• milli m 10x-3
• micro µ 10x-6
• nano n 10x-9
• pico p 10x-12