Voltage drop is defined as the amount of voltage loss that occurs through all or part of a circuit due to impedance.

Excessive voltage drop in a circuit can cause lights to flicker or burn dimly, heaters to heat poorly, and motors to run hotter than normal and burn out.

**Formula to calculate voltage drop.**

The resistivity value at 25 Celsius degree °C is 0.017 for copper and 0.0265 for aluminum.

**Example:**

Calculate the voltage drop of a copper wire of length 10 units , if the current passing through it is 20A , and its cross section area is 5 Square units.

Therefore, the voltage drop is 0.68 Volts.