Voltage [Deleted]

[ElectroMaster]

ElectroMaster submitted a new article:

Voltage - The electric pressure that must be applied to cause electron movement is called voltage. When such

The electric pressure that must be applied to cause electron movement is called voltage. When such a voltage is applied to a conducting medium, free electrons move progressively from atom to atom and constitute what is known as current flow. In electronic and electric practices, a continuous path for current flow is formed by interconnecting wires, controls, relays, transformers, transistors, resistors and many other components to form what are known as circuits. Such circuits serve many...

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[Ratchit]

ElectroMaster,

I disagree with much of the nomenclature and some of the material of the above article. I will enumerate what I believe to be the correct way of describing some of the electrical phenomena.

1) "Current flow" is a redundant and ridiculous expression. Charge does not flow twice. Current is already charge flow. Saying "current flow" is equivalent to saying "charge flow flow". One should instead say current exists.

2) What is "electrical pressure" or "electrical force" with respect voltage? I can't wrap my head around those definitions. So what is voltage? Energy is required to gather some charge carriers (electrons) and crowd them into a physical space. The more charge carriers one puts into the same space, or the more one crowds the same number of charge carriers into a smaller space, the more energy it requires. The amount electrical energy divided by the amount of charge is the voltage. So voltage is defined as the energy density of the charge (joules/coulomb in MKS units). So if there is a higher energy density (voltage) at one end of a resistor with respect to the opposite end, the electrical energy will flow through the resistor towards other end of lower energy density. And, of course, density is not pressure or force. Think of voltage as an electrical energy density.

3) Georg Ohm did not discover V=IR. V=IR is the definition of electrical resistance, and was known since the beginning of electrical science What Ohm did discover and publish was the concept of electrical linearity with respect to voltage and current that prevails in certain materials like metals. For that he was honored with an electrical unit named after him.

Ratch
Hopelessly Pedantic

 

[ElectroMaster]

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[Sceadwian]

George Ohm isn't even known so much for the concept of linearity, more that he actually did real world detailed experiments which showed that linearity was real for metal conductors under controlled conditions. The various things I've seen attributed to George Ohm since I've been studying electronics is very different from reality.

I never liked the the linking of voltage to the term pressure myself because it links too closely with the water analogy for electricity which doesn't reflect the reality which is electricity is more like waves traveling through water not water itself flowing. The electrons in an AC powered device never actually enter or exit the cable they simply vibrate in place, yet large amounts of energy are transferred. DC powered devices the electrons over a large enough period of time (depending on the current and conductor size) will actually eventually travel from one end of a wire to another, but if the conductors are valued to prevent ohmic heating will generally take a VERY long time to do so.

One ampere of current represents the exact quantity of electrons that flows past a given point in one second and is equal to one Coulomb.

I would recommend giving a concept of scale to the amp by including the actual number of electrons in a columb which is quiet large, gives a little bit of perspective. 6,241,000,000,000,000,000 is the approximate number.