I’ve heard the definitions of it being “energy transferred per charge”, “potential difference”, and “the difference between the electrons in the positive and negative terminals of a battery” but I still don’t really understand some of these definitions, and can’t really wrap my head around what exactly is it.
I also don’t really get how it is the thing that can “power up” a circuit (I might have misunderstood this part” and how the definitions above can be the same thing
In: Physics
This is a common sticking point for lots of people, so I have to ask where do these definitions lose you? A flow of electricity is *moving charges*, and voltage can be understood as the quantity of energy required to move a *unit* charge (any small reference charge – the SI unit being the *coloumb*) from one point to the other.
It’s equivalent to electrical pressure. The higher the voltage, the more current that can be “pushed” through a resistive path
Imagine a river of water flowing downhill. If you want to move the water uphill, it requires energy depending on how high the hill is. If you let the water flow downhill in a controlled way, you can extract work from it.
Voltage is for electric charge what hills and valleys are for mass. It makes charges in a given place want to move in a particular direction, and it takes work/energy to move a charge in the opposite direction.
It’s a little weird because there are negative charges that want to go uphill, but you can just imagine the landscape being upside-down for them
There are way smarter people than me that will chime in. But what I was taught in college, in the most basic terms, is this:
Amperage is work. That is, at least 1 electron being knocked off one atom on to another repeatedly along the exterior of a copper wire (or other medium) transferring the electron value from a point of high electrical value, to another point of lower electrical value.
This could be 1 electron at a time, or it could be lots. And since this typically occurs on the outside surface of a copper wire. The more strands you have the faster, and more electrons can transfer.
Voltage is pressure of the transfer of those electrons. The greater the difference between the high value and low value points? The faster and greater number of electrons will trans in an unregulated system.
Resistance is the amount of inefficiencies present either naturally, or artificially in a circuit. In a perfect example you might have point A that has a 5 electron value, and point B that has a 2 electron value. You connect the two points and you would have 1 electrons leap to point B with the 7th floating between the two points. (This isn’t factual but a representation of stasis).
In the real world nothing is perfect and all transfers cost something. So in this made up example, you might have 1 electron leap to point B. At the cost of the 7th electron leaving the total balance of 3 electrons in both points and stasis.
I hope this helps. And I’m sure there are at least some errors as they have learned a lot since I was in college.
If you move a conductor through a magnetic field, you can force the electrons out of their normal atomic orbits so that one end of the conductor has an excess of electrons (and therefore a negative charge) while the other end has a dearth of electrons, and is therefore positively charged. The same thing occurs chemically in a battery.
Likes repel, opposites attract. The negative charges are trying to get away from each other and the positive charges are trying to pull them back. So there is a “charge” difference between them. Provide a path for them to rejoin, and you have current flow (amps).
You can really get hung up with monikers like electromotive force, potential, voltage, etc., as well as electron flow vs hole flow vs “they’re not really orbits, they just kinda vibrate”.
If you’re going to be designing MOSFETs and such, that may all matter, but for an ELI5 visualization, don’t worry about it. At this point all that is much more confusing than enlightening.
You want to watch TV so you pick up the remote; press the on button and nothing happens; the battery’s dead. So, you replace it. Now the remote works and you can watch TV.
What changed? The circuit in the remote is the same, but you now have a live battery, able to supply power. This is the voltage. The ability to push electrons around a circuit. The more they’re pushed and the harder they work, the more energy is lost and the push gets weaker (which is why you probably had to press the button on the remote 2 or 3 times, maybe hold it down, the last few times before it completely gave up). The battery dies because the voltage has dropped to zero; i.e. the battery can’t push the electrons anymore at all.
What level are you trying to understand this at and what concepts are you trying to harmonize?
If you’re asking on a metaphysical, deep level what *is* voltage, then you’re asking for something way above ELI5 and possibly even in the realm of philosophy rather than science.
If you’re asking for a practical explanation such as connecting the ideas of electricity and voltage, then electricity is basically the presence of a voltage along a path. This basic conceptualization is generally explained via a comparison to water in pipes, where water molecules are electrons or “charges”, the pipes are the electrical circuit, amps/amperage is the amount of water flow, voltage is water pressure, resistance is resistance to the flow of water that has to be overcome for water to move through the system.
Now, looking at your examples:
If charges are water molecules and voltage is “energy transferred per charge” then it would be like the pressure of a water hose shooting out water. The water is the same but the speed of each molecule shot out changes. Each molecule’s energy changes as the water pressure changes. Same with electricity and voltage. The higher the voltage the more energy in each charge, so it can overcome greater resistance to its movement. For example, high voltage can cause electricity to “jump” or arc over air to another place, just like high water pressure can shoot a stream of water across air where otherwise it would just hit the ground.
“Potential difference”. To conceptualize this, think of a water tower. The higher the tower, the more potential energy the water in it has, for it to be able to distribute water over a larger area, or with more pressure to the same area. Same with electricity. Voltage would represent the potential for charges to be forced either across a larger circuit with the same resistance or a smaller circuit with higher energy per charge. In this sense, voltage differential between two locations (terminals) can be seen as the ability for charges to do work as they are pushed from one terminal to the other.
“Difference between electrons in the positive and negative terminals of a battery” this is the same as potential difference but worded differently. Take the idea of an old fashioned scale, where to balance both sides you have to have the same weight. Electricity is the same, in that if both sides of a circuit (terminals) have the same charge amount (weight), then nothing will happen. There is no difference, or the differential is 0. Voltage then can be conceptualize as how high one side of the scale is compared to the other side. More of a difference, more voltage. For a water analogy, it’s like having a water tower with lots of water trying to go through pipes to a reservoir beneath it. If the reservoir is empty, then the difference in water in each place is very large, i.e. voltage would be large, but as water goes from the tower to the reservoir the difference becomes less until it balances out. The voltage would decrease as charges balance out on either end (terminal) of the circuit until it gets to zero.
Imagine voltage as the “push” or “force” that makes electricity move through a wire, kind of like how a pump pushes water through a hose. Voltage is the strength of the push that helps electricity move.
Battery = Water Pump: Think of a battery like a pump for electricity. Just like how a pump pushes water, the battery pushes electricity through the wires.
Electricity = Water**:** Electricity is like water that flows through a hose (which would be the wire). The more the pump pushes, the faster the water flows.
Voltage is difference in charge between any two points. If one point is super positive and the other is super negative, and you connect them with a wire, then electrons are going to want to go from negative to positive. That’s basically it.
Voltage is related to amps because amps is how fast electrons move. A higher voltage = more charge difference = that electrons are going to move faster = more amps.
You don’t even need a wire for this to work. Wires are just nice because electrons move relatively freely in a metal. But if you have two points that have a big enough charge difference between them, electrons will travel from one side to the other. That’s what happens with lightning, or a static shock.
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