Electrical Circuits 
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OHM'S
LAW FORMULA
When voltage is applied to an electrical circuit, current flows in the
circuit. The following special relationship exists among the voltage,
current and resistance within the circuit: the size of the current that
flows in a circuit varies in proportion to the voltage which is applied
to the circuit, and in inverse proportion to the resistance through
which it must pass. This relationship is called Ohm's law, and can be
expressed as follows:
E = I R
Voltage
= Current x Resistance
E
Voltage applied to the circuit,
in volts (V)
I
Current flowing in the circuit, in amperes (A)
R
Resistance in the circuit, in ohms 
In
practical terms "V = I x R" which means
"Voltage = Current x Resistance".
1
volt will push one amp through 1 ohm of resistance.
NOTE:
E = IR, V=AR, or V=IR are all variations of the same formula. How you
learned Ohm's law will determine which one you will use. Personal preference
is the only difference; anyone will get you the correct answer. 