E=IR, where E is voltage, I is current, and R is circuit resistance. To find current, equation becomes: I = E / R This is a DC equation, however for general calculations it's functional for basic AC use as well.
It all depends, are you dealing with a series circuit or a parallel circuit.. you have to know the difference between a series and parallel circuits.Current changes when there's a short in the circuit. while in series circuit the voltage changes in the circuit..I attached a review for you, hope you like it.....
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