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Voltage: a force or a form of energy

Discussion in 'General Electronics Discussion' started by ramit36, Oct 11, 2012.

  1. ramit36

    ramit36

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    Oct 9, 2012
    What exactly is voltage, is it a force that is required to move an electron from one point to another or it is an energy required by an electron to move itself from one point to another. In various books this term "voltage" is sometimes referred as a force i.e. electromotive force (emf) and sometimes as energy that an electron needs to travel from one point to another. And since, there is a difference between the definition of "energy" and "force", we can not call voltage both i.e. energy as well as force. And according to me it is just a force and not an energy. But whenever i see this formula i get confused,

    Vab = dW/dq (voltage between points a and b)

    So, please if anybody who is clear about this thing or even want to share her/his views, your most welcome.
     
  2. ramit36

    ramit36

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    Oct 9, 2012
    I am not sure about this, but i am feeling like both the things that i wrote about voltage above are one and the same thing.
    Let's write the equation again but in the form of their units.

    volts = newton-meter/C

    Now, by seeing the above equation we can say confidently that volts is nothing but the energy required by an electron to move from one point to another, but at the same time if you look closely in the equation you will find that "newton-meter representing the definition of energy that is 'force * distance' and if you arrange the equation by taking coulomb (C) on the left hand side then we might say that i guess volts is written with respect to newton which is a unit of force but then again confusion comes when we look at the coulomb (C) which is a unit of charge, i mean how can it be a distance"
     
  3. twbranch

    twbranch

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    Oct 10, 2012
    Voltage is the measurement of electromotive force.

    kind of like newtons is a measurement of a force.
     
  4. ramit36

    ramit36

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    Oct 9, 2012
    Yes, you are absolutely right.
     
  5. BobK

    BobK

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    Jan 5, 2010
    Voltage is neither a force nor an energy. If it were, it could be measured in newtons or pounds (force) or in joules, or foot-pounds (energy). It is a potential difference. A potential is a scalar quantity than can be defined at any point in an electric field.

    You need to add charge to convert a voltage to a force or energy. 1 volt is the potential difference required to impart 1 joule of energy to 1 coulomb of charge. 1 volt / meter is the voltage gradient that will put a force of 1 newton on one coulomb of charge.

    The units of volage are J/C (Joules per Coulomb), or equivalently, N m / C (Newton Meters per Coulomb.)

    Bob
     
    Last edited: Oct 11, 2012
  6. ramit36

    ramit36

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    Oct 9, 2012
    Hey Bob!

    Voltage is neither a force nor an energy - i still think it's a force

    If it were, it could be measured in newtons or pounds (force) <joule is unit of energy i guess> - voltage is just name given to force in the field of electricity which is named after the inventor of electric battery i.e. Alessandro Antonio Volta. That is it voltage name is used in the electricity or electronics domain, anyway, this is what i think and i could be wrong but right now i will stick to my point.

    It is a potential difference - I agree with you completely.

    Potential is a scalar quantity - i am doubtful about my knowledge.

    You need to add charge to convert a voltage to a force or energy - This one is interesting. This is how i see it. I have got energy in my body so i can use my force to move some movable object over a distance. I'll apply force but i need an object so that i could say i have done some work. Similarly, i think about the voltage thing also. According to me you are talking about converting a force to a force, which is not right. I can't say i am 100% sure about my point but yes sure enough to go ahead with my studies.

    1 volt/meter is the voltage gradient - I seriously don't know this.

    units of voltage are J/C or Nm/C - agree with you 100%.

    Amit
     
    Last edited: Oct 12, 2012
  7. BobK

    BobK

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    Forces are measured in Newtons. How many Newtons is 10 Volts?

    Bob
     
  8. davenn

    davenn Moderator

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    Sep 5, 2009
    thats kinda irrelevent, sorry. just because you think its something doesnt make it so
    If you really want to learn and understand physics and say electricty then you really need to come to learn and understand what has been studied in detail by
    much more learned people that have come before you and I

    your logic goes like this .... I have a Toyota car, known by all to have come from a Toyota factory, but you want to call it a Mazda
    Sorry it doesnt work that way ;)

    Dave
     
  9. ramit36

    ramit36

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    Oct 9, 2012
    That's what i am trying Dave, trying to learn electronics. I have shared my doubts and questions and also what i think about that but still i am not feeling like i have understood.

    And Bob i seriously don't know that and i have already told you i think that it's a force but don't know whether it is actually a force or not. I just think that way. And now i think i need to study more. But thanks because what you have explained has also helped me. So, thanks Bob.
     
  10. BobK

    BobK

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    Jan 5, 2010
    Ramit,

    I say a voltage is not a force, and you say you still think it is a force. As, they say, you are entitled to your own opinion, but not to your own facts.

    Let me give you an analogy; Is the height of a dam a force? When you say you think voltage is a force, you are basically saying the same thing. The height of the dam can tell us how much energy we can get by allowing a kilogram of water to flow over the dam and through a turbine at the bottom. Voltage is analogous to the height of the dam, and charge is analogous to the mass of water. The voltage tells us how much energy we will get if we allow a coulomb of charge to flow from one voltage to a lower one, or equivalently, how much energy would be required to push a coulomb of charge from a lower volage to a higher one.

    Bob
     
  11. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    Yeah, it's more akin to a distance than a force.

    If you think of potential energy that is gained by raising a mass a certain distance, electrical energy is obtained by raising a charge to a certain voltage.

    Now, that's clumsily written, but the idea is that energy in the first case is related to both the distance and the mass, and in the second case the voltage and the charge.

    Think of charge like mass (buckets of electrons), and voltage like distance (how high you lift them before letting them fall back to ground to do work).
     
  12. ramit36

    ramit36

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    Oct 9, 2012
    All i can say right now is that Bob you are right, it's the energy that is required by or applied on a charge to move it from one point to another. And your analogy really worked for me, thanks. By the way my name is Amit.
     
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