Ohm’s Law: Simple Explanation with Statement and Formulas

What is Ohm’s Law? Explanation, Formula and Solved Example

Ohm’s Law

The relationship between Current through and Voltage across a conductor was first discovered by a German scientist George Simon Ohm. This relationship is called Ohm’s Law which can be stated as;

The Current “I” flowing through a conductor is directly proportional to the potential difference i.e. Voltage “V” across its ends provided the physical conditions (i.e. temperature, strain, etc.) do not change.

In other words;

In any electric circuit, the Current “I” is directly proportional to the applied Voltage “V” and inversely proportional to the total circuit Resistance “R” if the physical condition of the circuit remain unchanged i.e. (Temperature of the circuit does not change)

Mathematically,

I ∝ V   …   or   …   V ÷ I     =>     Where R = Constant

Where “R” is a Constant of proportionality and is called Resistance of the Conductor.

Current = Potential Difference ÷ Resistance

I = V ÷ R

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Formulas & Equations of Ohm’s Law

For calculation and simplifying of electric circuits (measuring of Current, Voltage and Resistance), we can use Ohm’s Law in the following three forms

1.

V = I x R

Voltage = Current x Resistance

Volt = Amps x Ohms (Ω)

2.

I = V ÷ R

Current = Voltage ÷ Resistance

Amps = Volts ÷ Ohms (Ω)

3.

R = V ÷ I

Resistance = Voltage ÷ Current

Ohms (Ω) = Volts ÷ Amps

Where:

• V = Voltage in Volts
• I = Current in Amperes
• R = Resistance in Ohms (Ω)

Better funny explanation of Ohm’s Law

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Or another funny way to explain Ohm’s Law

Click image to enlarge

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How to Solve Electric Circuits using Ohm’s Law

Ohm’s law can be used to simplify and analyze both basic and complex electric circuits. There are multiple versions and equations used to find the values of different quantities such as electric current, voltage and resistance of the circuit.

The following useful Ohm’s law chart and its related formulas are used to calculate basic electrical quantities and parameters, such as voltage, current, power, and resistance.

Good to know: You may use the following Ohm’s law calculators to calculate the physical electrical quantities with units.

• Power, Voltage, Current & Resistance (P,V,I,R) Calculator
• Ohm’s Law Calculator – P, I, V, R Calculator

Ohm’s law can be applied on a part or whole circuit at once. If applied on a whole electric circuit, the total voltage is divided by the total resistance of the circuit to know the value of total flowing current in the circuit. On the other hand, if you want to determine and calculate the current in a specific part of the circuit, you will have to divide that part voltage on the associated resistance of it.

Example:

If the apply Voltage across a Circuit is 50V, and a series connected Resistor in the circuit which resistance is 10 Ω, then what would be the Current in that Circuit?

Solution:

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