Electric current consists of moving electric charges.

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.

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

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.

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

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