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Voltage Drop Formula

Last updated date: 29th Feb 2024
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Voltage Drop

Voltage drop meaning when electric current flows through the voltage drop, the quantity of electric power produced or consumed is measured. The decrease in electric potential along the course of a current flowing in an electrical circuit is referred to as a voltage drop. It's also a technique that's similar to an electric circuit. Additionally, each point in the circuit can be given a voltage that is proportionate to its "electrical elevation." To put it another way, the voltage drop is the arithmetical difference between a greater and a lower voltage. Furthermore, the quantity of energy per second (power) given to a component in a circuit is equal to the voltage drop between the terminals of that component multiplied by the current flowing through it.

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How to Calculate Voltage Drop?


Generating the circuit and measuring the voltage drop using the voltmeter is one technique to resolve the voltage drop across the circuit component (current measuring device). Furthermore, they are designed to cause as low an impact to the function of the circuit to which they are connected as feasible. Furthermore, they do this by reducing the amount of current flowing through the voltmeter to the minimum feasible value.


All voltage dips and current flows in the circuit are represented by these equations.

Engineers can also change the values of the various components to create a final circuit that best serves the principle.


Kirchhoff's Current Law states that the total current flowing in and out of any junction of wires in a circuit is zero. Furthermore, KCL equations are charge conservation formulae.


Kirchhoff's Voltage Law states that the total voltage loss around any closed channel in a circuit is zero. Its equations also represent the concept of energy conservation.

Voltage Drop Formula

The voltage drop formula shows how the voltage source's provided power is condensed when an electric current runs through the devices that do not provide the electrical circuit's voltage.

Furthermore, voltage drops between the source's internal resistances and connections are undesirable since supply energy is wasted. Furthermore, because provided power performs a competent job, the voltage drop across active circuit parts and loads is preferable.

V = I × Z

V = IZ


I = refers to the current in amperes (A)

Z = refers to the impedance in omega (Ω)

V = refers to the voltage drop

Solved Examples 

Ex.1. Through a circuit, a current of 12A flows through that carries a resistance of 20 Ω. Find the voltage drop across the circuit.



Current = 12A

Impedance Z = 20 Ω

By using voltage drop calculation formula we get,

V = I × Z

V = 12 × 20 

V = 240 V

Hence the voltage drop is 90 V.

Ex.2 How to find voltage drop by using the voltage drop formula when a current flow is 17A through that carries resistance of 26 Ω.



Current = 17A

Impedance Z = 26 Ω

By using the voltage drop calculation formula we get,

V = I × Z

V = 17 × 26

V = 442 V

Hence the voltage drop is 442 V.

FAQs on Voltage Drop Formula

Q.1) What is the Potential Drop Formula?

Answer: Electrical impedance may be stated using the formula E = I Z, which is similar to Ohm's law for direct-current circuits. In an AC circuit, the voltage drop is equal to the product of the current and the circuit's resistance.

Q.2) What is the Formula for Voltage?

Answer: The potential energy difference between two places is known as voltage, and it is defined as the electric potential energy per unit charge.

Although the electric potential is a more correct phrase, because the volt (V) is the SI unit of electric potential, it's often referred to as voltage, especially when discussing the potential difference between the terminals of a battery or other portions of a circuit.

Q.3) What is the Voltage Drop Specification for Ground?

Answer: A voltage drop of 0.1 volts or less is common between the power and ground sides of a circuit. From one end of a copper wire or cable to the other, expect a voltage drop of 0.2 volts or less. A voltage loss of 0.3 volts or less is common for a switch.