Definition of Voltage Divider

 A voltage divider is also known as potential divider. It is a simple electrical circuit that contains a high resistance across a voltage source. We obtain the variable voltage output across the resistance by varying position of sliding contact on the resistance. This output voltage is a fraction of source voltage. Voltage divider rule is applicable for both AC and DC voltage source.

Voltage Divider Rule

Let us consider a circuit where a variable resistor is connected across a voltage source ( Battery ) E Volt. Let's assume, resistance between negative terminal and sliding contact of the variable resistance is r₁ and resistance between sliding contact and positive terminal is r₂. That means r₁ and r₂ are in series. Obviously current in this circuit loop is,
Since in series circuit, same current flows through the given resistors, voltage drop varies directly with its resistance.