Volt vs Ampere – Difference and Comparision

The one and the only difference between volt and ampere is that the volt is the SI unit of potential difference, voltage, and, electromotive force. Whereas, the ampere is the SI unit of the electric current.

Not to mention, there are some similarities between these two, about which we will talk in the later section. But, before going there, let me give you a brief review of the two in the tabular form.

 

Difference Between Volt and Ampere (Tabular Form)

  Volt Ampere
1. Voltage is measured in Volts. Current is measured in Ampere.
2. A volt is a derived unit. An ampere is a standard or base unit.
3. Mathematically, 1 volt is defined as Joule per Coulomb. Mathematically, 1 ampere is defined as Coulomb per second.
4. Sub-units of the volt are microvolt, millivolt, kilovolt, and megavolt. Sub-units of ampere are microampere, milliampere, kilo ampere, and mega ampere.
5. A voltmeter is used to measure the voltage in the given circuit. An ammeter is used to measure the current in the given circuit.
6. A voltmeter is always connected in parallel with the circuit or device to measure its voltage. An ammeter is always connected in series with the circuit or device to measure its current.
7. The symbol for volt is (V). The symbol for ampere is (A).

From the above volt and ampere comparison table, you got the exact overview of these two. However, in order to get to know them in detail, let us try to understand both of them in a detailed format. Keep reading!

 

What is volt in physics?

In physics, a volt is nothing but a measuring unit that measures the work done by an electric charge (electrons) to move from one end to another end of the given device or circuit.

In fact, a volt is not only the SI unit of voltage. It is also the SI unit of potential difference and electromotive force. It is represented by the symbol V.

Moreover, it is named after the famed Italian physicist Alessandro Volta who is often credited as the inventor of the first electric battery.

Mathematically, one volt is equal to the voltage or potential difference or electromotive force between two ends of the circuit that will allow one joule of energy per coulomb of charge that passes through it.

Not to mention, Volt comes in the category of derived units of measurement. WHY? Because it is derived from one of the seven base or standard units specified by the International System of Units (SI). The base unit of a volt is kg.m².s³.A¹.

 

Types of Voltmeter

A voltmeter is always connected in parallel with the circuit or device to measure its voltage. Not to mention, this measuring instrument can be used to measure both AC and DC voltage.

On the contrary, based on their display system, there are two types of voltmeters. These are analog voltmeter and digital voltmeter. Similarly, based on their constructional design, there can be the following types of voltmeter.

  • Permanent magnet moving coil voltmeter
  • Rectifier type voltmeter
  • Attraction type moving iron type voltmeter
  • Repulsion type moving iron type voltmeter
  • Electro-dynamometer voltmeter
  • Induction type voltmeter, etc.

 

What is an ampere in physics?

In physics, an ampere is nothing but a measuring unit that measures the rate of flow of electric current that flows through the circuit or the given device. It is represented by the symbol A.

Moreover, it is named after the famed French physicist André-Marie Ampère who is often credited as one of the founding members of classical electromagnetism.

Not to mention, an ampere comes in the category of base units. In other words, you can say that there is no way to derive ampere (A) from any other measuring units.

Conversely, you can also say that a volt (which is a derived unit) can be derived using ampere (which is a base or standard unit).

As you know that the ampere is one of the seven SI base units of measurement defined by the Internation System of Units (SI). Therefore, mathematically, an ampere is equal to the fixed value of the elementary charge (e) i.e equal to 1.602176 × 10−19.

Apart from ampere, the other base units of measurements are second (s), meter (m), kilogram (kg), kelvin (K), mole (mol), and candela (cd).

 

Types of Ammeter

An ammeter is always connected in series with the circuit or device to measure its voltage. Not to mention, this measuring instrument can be used to measure both AC and DC voltage.

On the contrary, based on their display system, there are two types of ammeter. These are analog ammeter and digital ammeter. Similarly, based on their constructional design, there can be the following types of ammeter.

  • Permanent magnet moving coil ammeter
  • Rectifier type ammeter
  • Attraction type moving iron type ammeter
  • Repulsion type moving iron type ammeter
  • Electro-dynamometer ammeter, etc.

 

Relation between volt and ampere

The volt and ampere are related to each other by Ohm’s law. Ohm’s law states that the current passing through the conductor is directly proportional to the potential difference applied across the two ends.

In other words, Ohm’s law describes a mathematical relation between volt (voltage) and ampere (current) at constant resistance (R).

I={\frac {V}{R}},

 

Where,

I = current passing through the conductor in units of Ampere.

V = voltage applied across the conductor in units of Volt.

R = Resistance of the conductor in units of Ohm.

 

Frequently Asked Questions

1. What do volts measure?

Ans. A volt is a measuring unit that measures the potential energy (voltage) that exists between the two points of the conductor.

2. How many watts are in an amp?

Ans. First of all, an amp is a short form of ampere. Moreover, since power is nothing but a product of current (ampere) and voltage (volt). Therefore, you can also calculate ampere in terms of other measuring units such as watts.

For that, all you have to do is to use the formula of Power i.e P = I × V. Conversely, in terms of Si units, Watt = Ampere × Volt. As a result, an ampere in terms of watts will be Ampere = Watt/Volt.

3. How many volts in an amp?

Ans. Again, using the same logic and formula, Ampere in terms of Volts will be Ampere = Watt/Volt.

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I am a mechanical engineer by profession. Just because of my love for fundamental physics, I switched my carrier, and therefore I just completed my postgraduate degree in physics. Right now I am a loner (as like ever) and a Physics blogger too. My sole future goal is to do a Ph.D. in theoretical physics, especially in the field of cosmology. Because in my view, every part of physics comes within the range of cosmology. And I love traveling, especially the Sole one.

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