Difference Between Watts and Volts

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Watts Volts Difference

Watts is the SI unit of power, and Volts is the SI unit of potential difference.

When we go to the electricity shop, we find a 9 Volt battery, 9 Watts bulb, and so on. However, we come across a question as to why there are so many units like Watts, Volts, Ampere, etc. 

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The units like Watts and Volts have a difference. 

Power is measured in Watts, while voltage in Volts. There is a difference between Watts and Volts. In this article, we will learn about the difference between Watts and Volts in a detailed manner.


Difference Between Watts and Volts

Now, let’s discuss the difference between Watt and Volt in tabular form:

Watts and Volts

Parameters

Watts

Volts

Definition

Power is the work/job done by an object in a unit of time.

Voltage is called the electric tension, which pushes charged electrons in the circuit. 

The potential difference between the two points is measured by the amount of work done in moving a charge from one point to the other.

SI unit

Watt is the SI unit of power.

Volt is the SI unit of the potential difference and the electromotive force.

Symbol

The notation for the unit of power is W.

The symbol for the unit of potential difference is V.

Measurement

In measuring realistic power, we use the unit of Watts.

To measure the small amount of voltage from the power supply.

Measuring instrument or device

The device used for measuring power is the power meter.

The device used for measuring the voltage in Volts is the Voltmeter.

Base unit

The base unit of Watts is kgm2s-3

The base unit of Volts is kgm2A-1s-3

The device needed for measurement

The wattmeter is a typical multimeter that measures watts unless both V and I are DC.

The voltage applied across the ends of the conductor does the work in pushing current from one end to the other in a particular direction. 


The device that measures the potential difference is called the voltmeter.

The voltmeter is connected parallel to the circuit.

Dimensional Formula

The dimensional formula for Watts is:

[M1L2T-3]

The dimensional formula for Volts is:

[M1L2T-3A-1]


What is Power?

The amount of work a body can do in a unit of time is called power. In simple words, power is the rate of performing any task.

The formula for power is :

                   Power = Work/Time

Thus the power of an agent measures how quickly it can do the work/job. When you take less time in doing any work, it means you have great power. If in case, you take a large amount of time to do the same work, it means you have less power.

So, power is inversely proportional to time. 

There are various formulas for power; these are:

  1. V x I

In unit: Volts x Ampere

Volt-ampere is the apparent power.

  1. W/t

In unit: Work/time

Joule per second

  1. P = F . v

In unit: Force x velocity

N . m/s


What is Voltage?

Voltage is called the electric tension or the electrical pressure, which pushes charged electrons from one end to the other in a specified direction inside the circuit. 

On connecting the battery to the circuit, the potential difference develops across the two points of the circuit. The difference developed, leads to the pushing of an electron. 

So, the potential difference between the two points is measured by the amount of work done in moving a charge from one point to the other.

There are various formulas for voltage; these are:

  1. P/I

In unit: Watt/Ampere

  1. IR

In unit: Ampere x Ohm

  1. W/q

In unit: Joule per coulomb


Difference Between Watts and VA

The below table lists the difference between Watts and Volt Ampere:

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Parameter for Comparison

Watts

Volt Ampere

Variation

Watts is of real power.

Volt Ampere or VA is apparent power. 

Symbol

Watts is symbolized as ‘W’

Volt Ampere is symbolized as VA

Formula for calculation

The formula for the power of an electric circuit when V and I are in DC (Direct current), i.e.:

 P = Vdc x Idc


For an AC supply, the formula becomes:


P =  ∫v (t) * i (t) dt

The formula for Volt Ampere is:

  1. Direct current supply

P = Vdc x Idc


  1. For an AC supply, the formula becomes:

P = VRMS x IRMS

Employed for

Used for evaluating heat produced or dissipated.

Calculating the cost of energy.

Sizing wires properly, circuit breakers, and fuses.

For adding multiple ratings together 

Add Watts reading linearly.

There is no straightforward method of adding VA together.


However, if added linearly, the result will be greater than the actual value.

(It’s because adding linearly will provide a conservative estimate).

Base unit

kgm2s-3

kgm2s-3

FAQ (Frequently Asked Questions)

1. What is the difference between Watt and Volt Ampere?

Watt refers to actual or real power, whereas Volt Ampere refers to apparent power. They both have the same formula, i.e,  a voltage (V) multiplied by Ampere (A). 


Therefore, a device or instrument measuring 4 Amperes at 130 Volts would be rated to 520 Volt Amperes or 520 Watts.

2. How do you convert Watts into Volts?

We know that the formula for converting Volts into Watts is:

                        W = A * V

For example, if a current of 5 A flow through the circuit at 30 V, then the power generated is:

                              P = I * V = 5 * 30 = 150 W 

This is how we can convert Watts into Volts. 

3. Do more watts mean brighter light?

Watts are the product of current and voltage. 

So, the Wattage of the light is the amount of energy it takes to produce a definite amount of light. The more is the wattage, the brighter is the light.

For example, 100 Watt incandescent lamp produces between 1700 and 1800 lumens of brightness by using 100 Watts of energy per hour per Joule.

4. What is Watt equal to?

In international systems, Watt is the SI unit of power. It is equivalent to 1/746 Horsepower.