What the heck is voltage, anyway?

[Gregg]

Another way to look at it that hasn't been mentioned yet:  Imagine the electrons lined up in the wire like balls in a Newton's cradle.  The electrons in a wire are more like this than water in a pipe in that a potential at one end doesn't cause electrons to zoom from that end to the other.  (It is really much more complicated than a Newton’s cradle, but I think it is a better image than a pipe and water for a beginner.)
The voltage can be imagined as the relationship of how high the first ball is raised (imagine a really long tether) and more importantly how much force it hits the stationary lineup to cause the reaction that makes the ball on the other end move away from the others.  The fact that the far end ball doesn’t move quite as far up as the initial ball is similar to resistance; in this case friction which causes heat (entropy).
If two balls are raised from the stationary group at one end and let go together, two balls will jump off the far end; twice the mass transferred is similar to twice the current.

[Brumby]

The only parameters there are amps - the number of electrons passing the finish line - and resistance, which I guess would be the width of the track.

Why would electrons want to move in the first place, and why in one direction of wire instead of the other?  They're being pushed by an electromotive force, EMF, measured in Volt.

I should have added that to my response.  The pressure I mentioned is EMF - which is, in fact, the EE term.  It's composition is rather self explanatory:  electro  ...  motive  ...  force.

[tpowell1830]

So, from your racetrack analogy where there are horses together in the same racetrack, the racetrack is resistance, but it never changes, but the horses are not the electrons, the riders are. The horses are the volts carrying the 'electrons' down the track. The horse with the highest volts carries the electron faster, where the resistance doesn't change,but the current does. The only reason the current changes is because of the higher voltage of the fastest horse, the winner. Work is done.

A bit of a stretch, but, maybe that works as an analogy that helps you understand?

[Brumby]

I can see you were trying to make use of the racecourse analogy - which is to be commended - but since that wasn't a good analogy in the first place, IMHO, it really didn't have much hope in aiding an explanation.  I just found your extension of it more confusing.

[P90]

For an intuitive understanding, It makes all sense in the context of ohm's law, which can be visualized like this:

I like this

[tpowell1830]

I can see you were trying to make use of the racecourse analogy - which is to be commended - but since that wasn't a good analogy in the first place, IMHO, it really didn't have much hope in aiding an explanation.  I just found your extension of it more confusing.

Oh, thanks for the commendation, I will cherish it, and I apologize if the analogy confused you. I realized that I was beating a dead horse  (pun intended), but the OP seemed to like the racetrack idea. My simple attempt at helping the OP understand using his own analogy.

[Brumby]

https://en.wikipedia.org/wiki/Electronvolt

I would not get too wrapped up in this.  The eV has a place in particle physics for convenience.

i have never tried to visualize voltage this way, but correct me if i am wrong

at the very instant of resisting (i would imagine this as stopping time?) 6.241509126 ×10^18 (1 coulomb) electrons from moving across 1 ohm
those electrons (1 coulomb worth?), will exhibit 1 volt potential across the 1 ohm. but how many electrons exactly?

Not quite right.  The 1V does not come from the electrons in the 1 ohm resistor.  It comes from the EMF that is applied to one end of the resistor*.  The electrons in the resistor don't create the 1V - they react to it, according to how the resistor allows.

same 1C of electrons over 10 ohms = 1volt, as 10x resistance only allow 1/10 C to pass per sec.

Again, the electrons in the resistor don't create the 1V - they react to it, according to how the resistor allows.

(which makes the volt = joule per coulomb, whats the scientific term for this? energy is conserved?)
so time is an essential part of this whole "voltage" thing, as x amount of electrons need to get "somewhere else" in an amount of time, that movement uses energy, and that is the description in volts.

You are mixing up 3 different quantities here: Charge, Energy and Work.  Only Work is dependent on time.

i then further think that, if our entire planet is at 1000volts, and nobody will feel a thing, because no electrons moved and no energy is used to move it to anywhere else potentially higher or lower,

In terms of electric current, you are pretty much correct.  There will, however, be an electrostatic repulsion between any two objects at 1000V

so actually voltage is just trying to tell me, energy differences between groups of electrons in different places at a certain time ( i probably went a little too far in my imagination of this 1 haha)

i guess the above is a sane explaination?

Again, time is not relevant, but the energy difference is a part of it.

this then i guess, will perfectly explain why in volt nutting, they use a "bridge" to measure voltage, as voltage visualized as a "pressure" stream of electrons meets another "pressure" stream on a "bridge" and no electron is moving anywhere as both sides have equal pressure, and on 1 side the "pressure" is counted to know whats going on the other side of the "bridge".

now this then leads to a "hole" in my brain, as this is call a voltage bridge, what is the term called for a 34401a DMM voltage measurement? ohmic something something bla bla? the "leaky" method of measuring voltage with volt meters. now i am thinking, it would be cool if someone miniaturize the "volt bridge" as a handheld voltmeter, ie : handheld voltmeter with infinite input impedance. volt nuts will need to rename the club, electron counting nut

The traditional multimeter presents a loading of the circuit under test.  Obviously the less, the better (under most circumstances**)  The less current drawn from the circuit, the less impact it will have on the measurement.  These days, it is common for a DMM to have the same loading on a circuit as a 10M ohm resistor - and they are able to do this quite inexpensively.  This is pretty high and is good enough for most common situations - even those where the measurement might be affected, an experienced person will have a feel for how much that effect might be - and be able to interpret the reading with some reasoning.

Certainly, the portable bridge meter is not an impossibility - but I'll leave comment on that to the volt nuts.

Edit: Missed these footnotes:
* Argument assumes a common connection exists as the 0V reference
** Sometimes, (as an example, an unconnected wire in an EM field) you will have a conductor that will show a misleading voltage if measured with a high impedance meter.  At such times, a meter that actually has a low impedance input will 'drain' such voltages and give a truer idea of the actual voltage on that conductor.  Dave's BM235 has such a range.

[CharlieWorton]

WOW!

That's an unbelievable response!  Thank you so much!!!

So I posted the topic and figured I'd let it simmer for a while... A day later, well, I didn't really think anyone would have bothered, but, you know, hope springs eternal...

HOLY SCHMOKES!

Thanks to IanB, rstofer, Sweeney, helius, forrestc, EEVblog, MrAl, FrankBuss, ggchab, Brumby, kalel, KL27x, took,i Shock, Mechatrommer, SoundTech-LG, Ratch, bson... This is just fantastic.

Someone - I forget who, perhaps more than one - posed the question "what is it that makes the electrons move?"  I read that, I had this sharp intake of breath, my eyes widened a little bit... and it all fell into place.

Voltage ain't a thing, like an electron.  It's a force.

In my 'electrons across the finish line' analogy, electrons with a tiny amount of voltage are weak little pencil necks who are easily dissuaded.  As they get more voltage - muscles - they get harder and harder to block.  And Shwarzenegger electrons have so much voltage behind them that they just blow a hole right through you, if you get in their way.

It's oomph.  Enthusiasm.

A force.

Got it!

People, this was massively helpful.  I spent most of the day at McDonalds ($1 soft drinks with free refills) with my laptop, studying away like a busy little beaver.  Just about ready to write my next exam - second in a series of 23 - and then on to the next module.

Oh, hey, FrankBuss - that was a hilarious cartoon!  I'm gonna print it out and put it in my hobby room.  When I get it finished, that is.  Almost finished clearing it out, then I have to paint it, then build some furniture for it.  It will be a combination Office/Electronics cubbyhole/3D printer cubbyhole/Library.  All in about 80 square feet of space.  Yeah, it's gonna be tight.

And here's something of interest:

You'll note the Rigol Oscilloscope, offered on Amazon for $8.28 Canadian.  Including shipping, no less.  So, what the heck?  I bought one.

Well, things that sound too good to be true, usually are.  It seems that Amazon has been infested with thousands of scam artists who set up as merchants in the Amazon Marketplace, list goods at attractive prices - sometimes laughably attractive - and just tell Amazon that they've shipped the goods.  On nothing more than a verbal statement and a fake tracking number from a nonexistent shipping company, Amazon then pays them in full.  But the goods were not shipped; in fact, they never existed.

So, I had a quiet chat with Amazon, and they are refunding me my $8.28.  Oh, and if the oscilloscope ever shows up, I get to keep it.  But I think the funniest part of the deal is the screenshot of the listing.

I'm working on a ridiculously tight budget, so - although I want one - I don't see an oscilloscope in the immediate future.  The Rigol comes in at around $600 Canadian with tax and shipping.  For about $400 I can get the Hantek DSO5202P from China.  2 channels, not 4; 200Mhz, not 100Mhz.  I don't see an immediate requirement for a scope, and the money really isn't in the budget anyway... I just want a scope.  So, if you have thoughts, I'm all ears.

Thanks again, everyone.  You really helped!

Thanks, Charlie

[3roomlab]

Not quite right.  The 1V does not come from the electrons in the 1 ohm resistor.  It comes from the EMF that is applied to one end of the resistor*.  The electrons in the resistor don't create the 1V - they react to it, according to how the resistor allows.

i knew there are problems the way i draw cartoons in my head.

i got the idea electrons create the potential difference because of this article
https://clectronics.wordpress.com/2015/07/19/radiation-sensor/
i think i mis-understand the eV (energy unit) as it is converted into a charge (coulomb unit) and an actual electron EMF value.

silicon converts 1.1eV energy into 1 free electron (or so i read?), i assume different particles reacts in different ways producing a different ratio?
so 5keV alpha produce 4545 pairs, create a charge of (4545 x 1.602e-19 =) 7.28e-16 coulomb, which on a 10pF photodiode appears as an EMF of 72.8uV.
the way the EMF appears (or how the alpha strikes the silicon) is the interesting part which i cant find information about. it is like a ring tone, you cant get out of your head 
(edit : it appears 1.1eV may not be the actual rate of impact ionization)

so with this, my understanding of EMF is the measurable force able to move charges around, time is not a factor. when charges start to move, energy is used, and this is where time is a factor. am i connecting the dots correctly?

[rstofer]

I'm working on a ridiculously tight budget, so - although I want one - I don't see an oscilloscope in the immediate future.  The Rigol comes in at around $600 Canadian with tax and shipping.  For about $400 I can get the Hantek DSO5202P from China.  2 channels, not 4; 200Mhz, not 100Mhz.  I don't see an immediate requirement for a scope, and the money really isn't in the budget anyway... I just want a scope.  So, if you have thoughts, I'm all ears.

Don't forget to include the new Siglent SDS1202X-E in your list of candidates.  It's only 2 channels but it is 200 MHz and, so far, people are enthusiastic.  Search the forum...

[Brumby]

Not quite right.  The 1V does not come from the electrons in the 1 ohm resistor.  It comes from the EMF that is applied to one end of the resistor*.  The electrons in the resistor don't create the 1V - they react to it, according to how the resistor allows.

i knew there are problems the way i draw cartoons in my head.

i got the idea electrons create the potential difference because of this article
https://clectronics.wordpress.com/2015/07/19/radiation-sensor/
i think i mis-understand the eV (energy unit) as it is converted into a charge (coulomb unit) and an actual electron EMF value.

silicon converts 1.1eV energy into 1 free electron (or so i read?), i assume different particles reacts in different ways producing a different ratio?
so 5keV alpha produce 4545 pairs, create a charge of (4545 x 1.602e-19 =) 7.28e-16 coulomb, which on a 10pF photodiode appears as an EMF of 72.8uV.
the way the EMF appears (or how the alpha strikes the silicon) is the interesting part which i cant find information about. it is like a ring tone, you cant get out of your head 

Discussion of the mechanisms involved in the photoelectric effect are a little outside the OPs original question - and I might suggest a separate thread with a more appropriate title will attract more interest.

so with this, my understanding of EMF is the measurable force able to move charges around, time is not a factor. when charges start to move, energy is used, and this is where time is a factor. am i connecting the dots correctly?

Basically, yes.

[Frankenbee]

Someone once told me to imagine a spark gap. High voltage will spark across a wider gap. Not sure if it's true but it helped me to visualize voltage better than the water analogy.

[Brumby]

Yes, it is true.

As for analogies, they won't always make sense to everybody - but for some they are a beacon of enlightenment.  That's just how they are.

For the water analogy, voltage is equivalent to pressure (it can actually be described as electrical pressure).  Think of a garden hose and a fire hose from a fire engine's pumps.  More pressure = greater distance ... just like your spark.

[MrAl]

Hello again,

Imagine you have 10 basketballs clustered together on the ground.  Now you take your hand and move 6 to the right and 4 to the left.  What is the difference from one side to the other?  The difference is 6-4=2.  Before you did that though there was no difference because there was only one group to consider.  Once you get two groups you see a difference, and that is similar to the way voltage is 'formed'.

Voltage is something you 'get' when you separate charge.  If you have ten units of charge and you move 6 to the right and 4 to the left, you have a voltage difference between the two groups.

So current is a movement of charge, and voltage results from a static separation of charge.  Once you separate charge the higher potential tries to shift toward the lower potential so we may see current flow.  It's a law of physics that everything has a natural tendency to minimize the energy.  We often like to force this to happen by using something like a battery so we can get things to happen that we like to have happen, like light an LED.

A little comical view is that we all like to spend money.  We have a group of coins in our pocket we would like to transfer to someone else so we can gain some sort of benefit.  Their hand is initially empty and our pocket is full, so we transfer some coins into their hand (current) and we gain some material benefit :-)

[rstofer]

I'm working on a ridiculously tight budget, so - although I want one - I don't see an oscilloscope in the immediate future.  The Rigol comes in at around $600 Canadian with tax and shipping.  For about $400 I can get the Hantek DSO5202P from China.  2 channels, not 4; 200Mhz, not 100Mhz.  I don't see an immediate requirement for a scope, and the money really isn't in the budget anyway... I just want a scope.  So, if you have thoughts, I'm all ears.

I think the beginner is better served with something like the Digilent Analog Discovery 2 because it is a complete lab in a box.  A small box!

Dual channel scope, dual adjustable power supplies, dual arbitrary waveform generator, 16 channels of digital IO that can be used as a logic analyzer, etc.  Download the free software and play with the demos...

I would recommend the Pro bundle:
http://store.digilentinc.com/analog-discovery-2-pro-bundle/

It's worth reading the product description or even heading over to the Resource Center
http://store.digilentinc.com/analog-discovery-2-100msps-usb-oscilloscope-logic-analyzer-and-variable-power-supply/

Do not underestimate the utility of this tool.

Back to voltage:  I think of it as a force and that is the limit in my interest of the physics involved.  It is the force required to get a certain current to flow through a specific resistance.