# Electric Current Formula – ElectricalEngineering.XYZ Formulas

Electrical current is a fundamental property associated with circuits. In this post ElectricalEngineering.XYZ presents all the important formulas you should know about Electric current.

Contents

- 1 Electric Current Formula By Definition
- 2 Electric Current Formula from Ohm’s Law
- 3 Electric current Formula when Power and Voltage is Known
- 4 Electric current formula from Power and Resistance
- 5 Electric Current Formula in Single Phase AC Circuits
- 6 Electric Current Formula in Three-Phase AC Circuits
- 7 Other Current Formulas

## Electric Current Formula By Definition

By definition electric current is defined as the rate of flow of charge.

1 Ampere is the current in circuit when 1 coulomb of charge passes through a given point in one second.

Mathematically

**I = Q/t**

where

I = current in amps

Q = charge in coulombs

t = time in seconds

## Electric Current Formula from Ohm’s Law

According to Ohm’s law, current is defined as ratio of voltage to resistance.

Mathematically

**I = V/R**

Where

I = current in amps

V = Voltage in volts

R = Resistance in ohms

## Electric current Formula when Power and Voltage is Known

Electric current formula can also be expressed in terms of power and voltage.

**I = P/V**

Where

I = Current

P = Power

V = Voltage

## Electric current formula from Power and Resistance

In case of know power and resistance the electric current formula is:

**I = √(P/R)**

where

I = Current

P = Power

R = Resistance

## Electric Current Formula in Single Phase AC Circuits

In case of single phase AC circuits the current formula is:

**I = P/(V * PF)**

Where

I = current

P = Power

V = Voltage

PF = Power factor (Cosθ)

## Electric Current Formula in Three-Phase AC Circuits

In case of three phase AC circuits the formula for current is:

**I = P/(V * PF * 1.73)**

Where

I = current

P = Power

V = Voltage

PF = Power factor (Cosθ)