Electric Current

1
Electric Current

• Electric current consists of moving electric
  charges.

2

• They can be moving in an uncontrolled path, such
  as in a lightening strike, or in a controlled
  once, such as any kind of electric circuit.

3

• Electrical current is the amount of charge that
  passes a point in a conducting wire every second.
  The symbol for current is I and the units are
  amperes (A).
• I Q current charge moving past a point
• t time

4

• The symbol for charge is Q and the units are
  coulombs (C).
• One coulomb is equal to 6.0 x 1018 electrons.
• For this equation to work the time must be
  measured in seconds.

5
Example A

• If 240 C of charge pass a point in a conductor in
  5 min, what is the current through that point in
  the conductor?
• Given Q 240 C t 5.0 min
• Convert 5 min to seconds 5.0min X 60s/1 min
  300s
• I Q 240C 0.80 A
• t 300s

6
Example B

• If a radio used 0.4 amps and is run over 10
  minute period what is the charge that passes
  through it?
• Given I 0.4 A 10 minutes
• Convert 10 min to sec. 10.0 min x 60s/1min 600s
• Q I t (0.4 A) (600s) 240 C