Download Electric Current - Wissahickon School District

Electric Current
Chapter 7 section 2
Electric Current
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Electric current- The flow of electrons through a wire
or any conductor.
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Measured in units of Amperes (A)
Charges flow from High voltage to Low voltage
Voltage difference- push that causes charges to
move- measured in volts (V)
For charges to flow, the wire must always be
connected in a closed path, or circuit
http://www.school-for-champions.com/science/dc.htm
Resistance
Resistance- the tendency for a material to
oppose the flow of electrons, changing
electrical energy into Thermal energy and
light
 Resistance is measured in Ohms (Ω)
 Making wires thinner, longer, or hotter
increases the resistance
 Ohm’s Law- the current in a circuit equals
the voltage difference divided by the
resistance I = V/R
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Electrical Circuits
Less resistance means less heat, which is
safer for use in your home
 As resistance increases, current
decreases
 As voltage difference increases, current
increases
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Sources of Electricity
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A Dry Cell battery produces a voltage
difference between its zinc container and
its carbon suspension rod, causing current
to flow between them.
Sources of Electricity
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A Wet Cell battery contains two connected plates
made of different metals in a conducting solutionlike a car battery
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Electrical Outlets- have a voltage difference across
the two holes of an electrical outlet and a generator
at a power plant provides the voltage difference
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Resistance- the tendency for a material to oppose
the flow of electrons, changing electrical energy into
Thermal energy and light
Electrical Circuits
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Series circuit- current has only one path to flow
through
Parallel circuit- current has more than one path
to flow through
Magnetic fields form around wires through which
electricity is moving
Electromagnet- a temporary magnet made by
placing a piece of iron inside a current-carrying
loop of wire
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More loops = stronger
More voltage = stronger
Only works for DC current