Transcript Electricity and Electronics

Electricity and Electronics
Brad Dearing
108 University High School
Normal, IL 61761
(309) 438-5513
[email protected]
The Nature of Matter
• Matter – anything that has mass and takes up space.
– Element – the most basic form of a substance.(Sodium) or
(Chlorine)
• Compound – the combination of two or more elements. (Salt)
• Molecule – the smallest part of a compound that still retains its
unique properties. (One small piece of salt)
– Atom – smallest part of an element (one sodium atom)
• Electrons – Negative part of atom (11 electrons in Na)
• Protons – Positive part of atom (11 protons in Na)
• Neutrons – No charge or neutral part of atom (11.990 neutrons in
Na)
Ionization
• Ionization occurs when an atom gains or
loses an electron.
– Positive Ion – more protons than electrons in an
atom (loses an electron)
– Negative Ion – more electrons than protons in
an atom (gains an electron)
Static Electricity
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Electricity at rest (static)
Stationary charge
Produced by friction
Law of charges: Like charges repel each
other and unlike charges attract each other.
Terms
• Coulomb – the measurement of the amount of
electricity. 1 coulomb = 6.24 x 1018 electrons
• Electrostatic Fields – the field of force
surrounding a charged body. (dielectric field)
See next slide
• Induction – the transfer of a charge without
direct contact, bringing it close to another
object.
Basic Electrical Circuit
• Source of voltage (battery)
• Load (lamp)
• Conductors (wires)
Polarity
Terms
• Battery – form of DC electricity, generally by
chemical reaction.
• Load – when electrical energy is converted to
some other form of energy. (i.e. light, heat,
magnetism, etc.)
• Conductor – pathway conducive to carrying
electricity, generally coated with a protective
coating.
Terms
• Voltage – the force behind electron flow.
(volts: V) aka: potential, potential difference,
or electromotive force (emf) (E)
• Current – the flow of electrons. (ampere: A)
(I) 1 amp = 1 coulomb of charge flowing past
a point in one second.
• Resistance – the opposition to the flow of
electrons. (ohms: )
Terms
• Conductor – anything that permits the free
flow of electrons.
• Insulator – extremely poor conductors.
• Semiconductor – a material that limits the
flow of electrons, considered neither a good
conductor nor a poor conductor.
See table of common conductors and insulators p. 27
Current
• AC – Alternating
Current: flows in
both directions.
(household current)
(Cycle or hertz: Hz)
• DC – Direct
Current: flows in
only one direction
in a circuit.
(battery)
Electron Flow Theory
• Conventional current
flow theory – positive to
negative.
• Electron flow theory –
negative to positive.
Series and Parallel
voltage
Ohm’s Law
E=IxR
I=E/R
R=E/I
current
resistance