OHMS LAW CALCULATOR

v = i * r  [Voltage(v) = Current(i) * Resistance(r)]

p = v * i  [Wattage(p) = Voltage(v) * Current(i)]

By Lucien LeSage


NOTE: Enter any two, but only two variables to calculate missing variables and calculate wattage if not one of the known varables.

Voltage (v)
Current (i) in AMPS
Resistance (r) in OHMS
Wattage (p) of device

 

Ohm’s Law Explained

Ohm’s law relates that the voltage difference between two points, the electric current flowing between them, and the resistance of the path of the current are all proportional and related to each other.

Ohm's Law explains the relationship between voltage(v), current(i), and resistance(r) by stating that the current through a conductor between two points is directly proportional to the potential difference across the two points. (v=i*r)

This can be expressed mathematically in the following equations in terms of V the voltage difference, I the current in amperes, and R resistance in ohms.

What this means in practical terms is that the current passing across a two-terminal device like a resistor with a fixed value of resistance is directly related to the voltage difference applied across the terminals.

That means for a given constant voltage, higher resistance entails lower current flow. And the reverse is also equally true, for the same given constant voltage, lower resistance would mean higher current flow.

Power or wattage is equal to the voltage in volts time the current in amps. (p=v*i). For example if you had an electric heater or hair dryer that was rated at 1200 watts and it's plugged into a 120 volt outlet then that heater will draw 10 amps (i=p/v).

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