Ohm's Law

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Ohm's law states that

"the current through a conductor between two points

is directly proportional to the potential difference or voltage across the two points, 

 and inversely proportional to the resistance between them".

Ohm's law can be expressed as 

I = V / R   (1)

where 

I = current (amperes)

V = potential difference (volt)

R = resistance (ohms)

Example - Ohm's law

A 12 volt battery supplies power to a resistance of 18 ohms. The current can be calculated as

I = (12 Volts) / (18 ohms)

    = 0.67 Ampere

Equivalent Expressions

Equivalent expressions of Ohm's law (1) are

V = R I  (2)

or 

R = V / I   (3)

Power

Electrical power can be expressed as 

P = V I  (4)

  = R I² 

  = V² / R

where 

P = electrical power (W)

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Related Topics

• Electrical - Amps and electrical wiring, AWG - wire gauge, electrical formulas, motors and units

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