Need serious help understanding basic electricity

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Old 05-10-12, 09:18 PM
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Need serious help understanding basic electricity

Hi folks,

I have a tall order and it's been unfulfilled for many, many years.

I am proficient in many scientific concepts but I cannot for the life of me understand basic electricity.

The only course in school, back 30 years ago, that I ever failed is electricity. And I failed it twice back to back before I gave up so I could just move on.

Today, with the advent of wikis, I would spend countless evenings, nights and weekends, reading on different aspects of electricity before I hit a wall, perhaps the same wall that I cannot put a name on and that is preventing me from understanding electricity in a way that I can use it as a tool in my DIY daily life.

I don't know where to begin really, but I suppose that I can pick one aspect of electricity that I cannot understand as a means to get my thread going; so my question is this:

Simplified, why is a coulomb defined as a factor of amps per second and an amp is defined as a factor of coulomb per second? This is driving me nuts!

Let me say that I actually have a very good understanding of what happens in the world "below" the atom; the subatomic world. I can build up this understanding to the point where I begin to be exposed to the world of the atom and to the idea that it is made up of a nucleus with electrons in orbit around it.

So far so good.

At that point, building my understanding one more level up I am introduced to the concept of the electron as having an "Elementary Charge", of notation little e (actually -e, whereas the proton has an Elementary charge of +e).

Ok, so far so good.

Now it starts to get difficult for me because little e, the Elementary Charge, is defined as being "1.602 x 10 exposed to the -19" coulombs.

Okay... I don't know how I could draw you one single coulomb and so I wonder what the heck a single coulomb is; let alone 1.602 x 10 ex-19 worth of it...

So I lookup what a coulomb is and it's defined as being the charge of one amp in one second...

Okay... I don't know how I could draw you one single amp and so I wonder what the heck a single amp is; and apparently it is... Are you ready? It is ONE Coulomb per second.

!!!

So one coulomb is one amp per second and one amp is one coulomb per second???

Just shoot me!

At this point I'm am utterly lost; give me a soother and wrap me up in blanky to shield me from this horror.

I just don't understand this.

So those are definitions of electrical things having movements per second....

Well then let me ask you, what do you call 1.602 x 10 ex-19 electrons sitting together not moving ? In no amount of time?

A pack of electrons? What is that called?

There is alot more I could write and I'm not even sure this is the right place to start discussions but I thought I would start with this.

If anyone has any idea of to help me understand even this part then maybe i'll be able to move on and build up my understanding to the point where I can harmonize it with the understanding that I do have of a 1.5 Volt battery being able to power a certain wattage of light bulb.

Thank you very much,

Flood
 
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Old 05-10-12, 09:47 PM
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what do you call 1.602 x 10 ex-19 electrons sitting together not moving ? In no amount of time?
A dead circuit. Electricity only really exists in motion.

An electric current of 1 Ampere represents 1 Coulomb of unit electric charge carriers flowing past a specific point in 1 second. No motion = no amps = no coulombs = no electricity.
 
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Old 05-10-12, 10:18 PM
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Nashkat1,

Thank you very, very much.

Fair enough. I get a good part of your reply.

Interesting... I need to massage this.

It's late at night for me and I think I need to give this more thought so I can have a more sensible response.

Can you believe, only at this point, I have already read and reread your reply about 20 times?

Thank you.
 
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Old 05-11-12, 12:08 PM
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Quite honestly, unless you are teaching physics classes there is no need to know anything about Coulombs. I suggest reading the book, There Are No Electrons: Electronics for Earthlings by Kenn Amdahl. It is available from Amazon and even for the Kindle.
 
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Old 05-11-12, 12:54 PM
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Nashkat1,


Surely there can be more to be said about those electrons before they are being put in motion and put to work as it relates to what is intended for them.


Let's say you have one electron available for use, sitting there, doing nothing. Let's say that this electron can pass through a circuit composed of a positive and negative poles, a switch and a gate, both of which are opened, and that by manually flicking the switch the electron is able to flow through the circuit, pass through the gate and cause it to close.


Considering this scenario, questions that come to mind for which I know not the answers are:


- Before the switch is flicked, what would you say of this electron? That it has what, a charge? A potential? If a charge, then what is that charge, 1e (1.602◊10 ex−19 coulombs)? Would that be the correct way to say it?
- When I flick the switch, the electron passes through the gate, does it actually come out the other side or does it get consumed?
- If it does not get consumed, is it still available to close another gate if I were to have a second one in the circuit?
- By that point, with this electron going around the circuit (once), how would I calculate the voltage?
- Is the voltage the same on either sides of my gates?
- After the electron has gone around the circuit and done some work for me by closing 2 gates I now have nothing left on my negative pole. Is my electron now sitting on the positive pole?
- If so, and if my circuit is still closed, what is preventing my electron from flowing back the other way?


Those are just some of the inquiries that come to mind.


Any input greatly appreciated.


Thank you,


Flood
 
  #6  
Old 05-11-12, 12:57 PM
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Thanks Furd,

Hm.. I see.

I am very curious about the coulomb. I bring it up again in my reply just a couple minutes ago to Nashkat1's post.

- Flood
 
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Old 05-11-12, 01:12 PM
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Simplified, why is a coulomb defined as a factor of amps per second and an amp is defined as a factor of coulomb per second? This is driving me nuts!
The coulomb is used to indicate the charge. A charge that an object receives is determined by the number of electrons that the object gained, or lost. So if an object has a negative charge of 1 coulomb, it has gained billions of billions of extra electrons [6,280,000,000,000,000,000). Now, an electromotive force is produced when two charges have a difference of potential. This strength is indicated by the unit volts. With that in mind, lets move forward to current (ampere). Current (or the quantity of) flowing in a conductor is determined by the number of electrons that pass a given point in one second. Now, if we look above (again) we mentioned that a coulomb is billions (+) of electrons. So if one coulomb passes a point in one second, then one amp of current is flowing. And if a difference of potential is presented, then the difference will cause one coulomb of current to do one joule of work, the electromotive force is then 1 volt.
 
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Old 05-11-12, 02:03 PM
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- Before the switch is flicked, what would you say of this electron? That it has what, a charge? A potential? If a charge, then what is that charge, 1e (1.602◊10 ex−19 coulombs)? Would that be the correct way to say it?
That it has potential.

- When I flick the switch, the electron passes through the gate, does it actually come out the other side or does it get consumed?
It does not get consumed. In AC, it will come out the other side and then go back the way it came from - 60 times a second.

- If it does not get consumed, is it still available to close another gate if I were to have a second one in the circuit?
Sure.

- By that point, with this electron going around the circuit (once), how would I calculate the voltage?
See SeaOn's post.

- Is the voltage the same on either sides of my gates?
Yes, essentially.

- After the electron has gone around the circuit and done some work for me by closing 2 gates I now have nothing left on my negative pole. Is my electron now sitting on the positive pole?
It never left it. You're confusing electrical force with water flow.

- If so, and if my circuit is still closed, what is preventing my electron from flowing back the other way?
It already did!
 
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Old 05-11-12, 06:50 PM
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SeaOn,

Thank you.

That is very, very interesting. I read Member's responses... I let it simmer in my mind... Come back to it later and find I have a bit more understanding than before; this works great.

The coulomb is used to indicate the charge. A charge that an object receives is determined by the number of electrons that the object gained, or lost. So if an object has a negative charge of 1 coulomb, it has gained billions of billions of extra electrons [6,280,000,000,000,000,000)

Gain electrons, as in gain a charge, as in "recharge", as with a battery. OK, I'm with you.

Now, an electromotive force is produced when two charges have a difference of potential. This strength is indicated by the unit volts


Question, other than with the case of 2 objects that actually happen to have no electrons at all, hence, no charge, hence no difference of potential, what scenario could there be of 2 objects that have a certain charge but no difference of potential between them? Would such a case even be possible?

In the same token, could you say that 2 objects who have gained a charge of 1 coulomb of the same polarity, say of positive charges, would actually have a difference of potential of 1 volt of repulsive force?

Current (or the quantity of) flowing in a conductor is determined by the number of electrons that pass a given point in one second... ...
if one coulomb passes a point in one second, then one amp of current is flowing

OK, that's good, I get that too. But I am still struggling with what you say next:

And if a difference of potential is presented, then the difference will cause one coulomb of current to do one joule of work, the electromotive force is then 1 volt

Would it be correct to say that the difference of potential must have already been there in order for the 1 amp of current to be able to flow?

Also I wonder: That potential that you are talking about last, does it have to be of a certain, specific value or amount in order for the 1 amp to flow? Or is it rather that the minute that there is any potential of any order the 1 amp will flow? Actually, I'm catching myself here, it's the coulomb that is flowing in this example, and if it happens to flow in a second, we have 1 amp; whereas if it were to flow faster, say in half a second... We would have.. 2 amps? What could cause it to flow faster... More potential? More charge?

- Flood
 
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Old 05-11-12, 07:22 PM
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Nashkat1

Great, thank you very much, that clarifies some points.

I've got questions on AC vs DC. AC is what we have in our houses in Canada and is so because of, for example, the way I know Hydro Quebec generates its electricity via a dam where the flow of water going through magnet-equipped turbines of alternate polarities cause a push and a pull on electrons in the wires, hence producing AC current which you say alternates 60 times per second; is this number a North American standard or World standard?

With this AC current do you happen to know whether it has this number (frequency?) because of the way we generate it or because of some natural, physical law, rule, limit, etc ?

If what this alternation is, would you call it frequency, or oscillation or? Is it in Hertz?

Does it fluctuate at all? Or is it stable, rock solid?

Another thing I wonder is what happens to the concept of distance, with regards to AC. Do you know how much distance a coulomb covers in our electrical grid when it flows one way before it alternates and flows back the other way?

At this point, I'm pretty sure that you wonder how it even matters and I'd understand, and for the purpose of lighting a bulb, it probably doesn't matter one bit but still, I wonder.

Does it cover the same distance when it flows back as it did when it flowed forward?

Other than with some loss, say in the form of heat, or due to interference, would you say that it is practically the same electrons that go back in forth, continuously, over that distance?

As for DC, this is what we have in AA batteries and the like, correct? So in the circuit that I used as an example in my previous post, if I were to use DC current, would an electron flowing through the gate be consumed?

Thank you,

- Flood
 
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Old 05-11-12, 09:00 PM
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I've got questions on AC vs DC. AC is what we have in our houses in Canada and is so because of, for example, the way I know Hydro Quebec generates its electricity via a dam where the flow of water going through magnet-equipped turbines of alternate polarities cause a push and a pull on electrons in the wires, hence producing AC current which you say alternates 60 times per second;
IIRC, we use AC out in the real world for two reasons: 1> Thomas Edison lost the fight and 2> AC is a more efficient form for transmitting power.

is this number a North American standard or World standard?
North American

With this AC current do you happen to know whether it has this number (frequency?) because of the way we generate it or because of some natural, physical law, rule, limit, etc ?
It's a standard, or rule, that we adopted.

If what this alternation is, would you call it frequency, or oscillation or? Is it in Hertz?
Yep. 60 oscillations/sec = 60Hz = 60 oscillations/sec.

Does it fluctuate at all? Or is it stable, rock solid?
I don't know. My sense is that it's pretty stable, because much variation might harm or destabilize some devices. OTOH, I did see something in another thread about how electric clocks used to be designed to regulate themselves off of it and no longer are, allowing for greater fluctuation.

Another thing I wonder is what happens to the concept of distance, with regards to AC. Do you know how much distance a coulomb covers in our electrical grid when it flows one way before it alternates and flows back the other way?
No. Probably a sub-atomically small distance. BTW, you seem to be imagining a coulomb as a real object, with mass and density and all that. In fact, the coulomb is a dimensionless quantity.

At this point, I'm pretty sure that you wonder how it even matters and I'd understand, and for the purpose of lighting a bulb, it probably doesn't matter one bit but still, I wonder.
S'OK. If no one had ever wondered about these things we wouldn't have electric power today. And if everyone quits wondering about them, we'll be stuck with no further progress.

Does it cover the same distance when it flows back as it did when it flowed forward?
Sure, why not? Dimensionless is dimensionless, right?

Other than with some loss, say in the form of heat, or due to interference,
Heat generation isn't loss. Sometimes, if we want to heat our water or our food or our home, heat is exactly what we want as the primary work product. At other times, we like to minimize the amount of heat (IR spectrum) and maximize light (visible spectrum) or mechanical movement (a ceiling fan or a subway car). Either way, heat generation isn't loss. It's just part of the work performed.

would you say that it is practically the same electrons that go back in forth, continuously, over that distance?
Electricity isn't consumed. Electrical conductors aren't consumed. The molecules, atoms, electrons, protons, positrons, yadda, yadda in the conductor aren't consumed. I have no idea which electron is excited enough to dance, skip or vibrate at any given nano-second.

As for DC, this is what we have in AA batteries and the like, correct? So in the circuit that I used as an example in my previous post, if I were to use DC current, would an electron flowing through the gate be consumed?
No.

Read more: http://www.doityourself.com/forum/el...#ixzz1ucdTCOyN
 
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Old 05-12-12, 02:08 AM
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Nashkat1

Thanks once more for taking the time to answer my inquiries and I really appreciate how you are engaging.

IIRC, we use AC out in the real world for two reasons: 1> Thomas Edison lost the fight and 2> AC is a more efficient form for transmitting power.
Yes. I've seen a couple documentaries over the years about Tesla and Edison; what an incredible duo. I also really liked the references to Tesla in the movie The Pledge. And to think that the light bulb was apparently invented not by Edison, contrary to popular belief, but rather by someone else about 40 years before that!

Yep. 60 oscillations/sec = 60Hz = 60 oscillations/sec

Looks like we missed a great opportunity there to base the AC frequency on the metric system and make it, say, 100Hz. Although we probably had not come up with that system yet at the time. If that's correct then it probably made sense to chose 60Hz since there are 60 secs in a min, 60 mins in an hour... Still I wonder whether 100Hz was considered and if so, why it got dropped in favor or the the 60Hz choice; or I wonder even why we chose 60Hz altogether over any other number.

My sense is that the frequency is probably pretty stable because much variation might harm or destabilize some devices.


On the point of frequency stability I find it hard to believe (likely because I don't have all the facts) that the electric current would not fluctuate over long distances throughout the grid. My bet is that we must have had to come up with a way to resync or force the current back into our preferred 60Hz target at rather regular points along the grid. But you know, if I knew more about what actually is going on in the wires when electric current flows then I might be better able to understand the reasons behind these judgment calls that we made with regards to the AC frequency. Which brings me to the other point:

BTW, you seem to be imagining a coulomb as a real object, with mass and density and all that. In fact, the coulomb is a dimensionless quantity.

I would like to think of the coulomb as more than a dimensionless quantity, though I recognize that I might have to give it up. I am a very visual person as you might have guessed by now and for me to have a way to frame a coulomb in my mind is something that I believe to be essential in my making a breakthrough in understanding electricity at that higher level.

Take the LHC for example. As you probably have already heard, it propels a subatomic particle along a 27km radius across the border of two countries at a predetermined speed that directly determines the kinetic energy that the particle amasses. I find it extremely easy to picture this in my mind and that helps me understand very well the experiments that they are carrying on at this facility.

Oh and we're talking about just a one-on-one particle collision at that LHC; though these collisions are generated thousands of times per second (if not, more).

In fact, that makes that more sense to me knowing that when the LHC collides a particle with another the energy that is released at the point of impact has been said to be great enough to cause an oil tanker to move about 10 meters (I can't remember the exact number right now).

So to me electricity, electrons, electric charge, what it is, how it moves, the properties that it has, how it behaves, how it is malleable, useful and put to work means everything.

Mind you, by the time I understand this well, whether we are talking about one coulomb or one single electron probably will not matter much to me. I understand though that in different contexts or at different levels it is easier to make abstraction of the physical properties of one electron, or of an entire coulomb, as it applies to the matter at hand.

Heat generation isn't loss. Sometimes, if we want to heat our water or our food or our home, heat is exactly what we want as the primary work product...


Right and I totally get that. What I had in mind when bringing up possible heat loss was that there are certain applications where you incur loss of electrons in your circuit in the form of heat (apparently), such as is the case in today's CPUs or for the next generations thereof. Apparently circuitry in CPUs is being fabricated nowadays at such a small scale that leaks occur where electrons escape the circuit and produce heat that hampers the proper functioning of the CPU. It is thought that within a few years this leak will become so great that it will no longer be possible to have CPUs reliable enough to perform anymore computations.

Finally, I know you say one electron does not get consumed when it performs some work. So if I consider this then it would seem to indicate that at any point along a circuit, you have the same amount of electrons available to perform the same amount of work, is this correct?

And it would be so regardless of whether we are talking about an AC or DC circuit; correct?

Thank you,

- Flood
 

Last edited by Flood; 05-12-12 at 02:54 AM.
  #13  
Old 05-12-12, 07:56 PM
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Thanks once more for taking the time to answer my inquiries and I really appreciate how you are engaging.
I'm enjoying this, actually. It's a nice break from talking wires and terminations and devices, and it's an honest engagement. Thank you for naming that. So, to return to the discussion:

On the point of frequency stability I find it hard to believe (likely because I don't have all the facts) that the electric current would not fluctuate over long distances throughout the grid. My bet is that we must have had to come up with a way to resync or force the current back into our preferred 60Hz target at rather regular points along the grid.
The frequency is pretty stable over distance. The voltage will drop, though. Our two primary solutions for that are 1> to energize the grid at very high voltages and 2> to install, as you surmised, booster stations along the way.

I was reading an article a few weeks ago that laid out a plan for building a supergrid for North America. As part of that, they described and analyzed our existing transmission infrastructure. You might find it interesting. If I can turn it up, I'll post a link here, or a reference (it was in print, not online). BTW, did you know that Japan has two separate power systems - one for the northeastern part of the country and one for the southwestern part - and that they can't connect them to each other because the frequencies don't match?

I am a very visual person as you might have guessed by now and for me to have a way to frame a coulomb in my mind is something that I believe to be essential in my making a breakthrough in understanding electricity at that higher level.
I get that. I also enjoy the wave vs. particle debate going on about the nature of light. Each way of looking at it has some verifiable - observable - connections to our observed and theorized knowledge, but neither way matches everything we think we know. And I see parallels between that discussion and any discussion of the nature of electricity. Because both are energy. Each is a force.

You seem to be working on a particle theory for electricity. I'm wondering how it might work if you tried thinking of it as a wave instead.

Take the LHC for example. As you probably have already heard, it propels a subatomic particle along a 27km radius across the border of two countries at a predetermined speed that directly determines the kinetic energy that the particle amasses. I find it extremely easy to picture this in my mind and that helps me understand very well the experiments that they are carrying on at this facility.

Oh and we're talking about just a one-on-one particle collision at that LHC; though these collisions are generated thousands of times per second (if not, more).
I almost said, in my earlier post, "We're not talking fission or fusion here." And we're not. That's why we can safely invite the lightening we've tamed into our homes.

Finally, I know you say one electron does not get consumed when it performs some work. So if I consider this then it would seem to indicate that at any point along a circuit, you have the same amount of electrons available to perform the same amount of work, is this correct?

And it would be so regardless of whether we are talking about an AC or DC circuit; correct?
Yes, and yes

It occurs to me that many of the materials that are good conductors of electricity are also good conductors of heat. I'm still using some cast iron cookware that my mother acquired before I was born. I expect to pass it on, along with some copper utensils I've acquired, to my children and grandchildren. Nothing has been lost or consumed from the materials that these are made of, even though they have been used to conduct an immeasurable amount of heat to food over the decades they've been in use.
 
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Old 05-13-12, 02:06 AM
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Nashkat1,

Thank you very much for yet another enlightening reply; glad to know that you're enjoying this conversation as well.

Talking wires and terminations and devices will hopefully be me in the not-too-distant future given that I actually put a few DIY electric projects on hold in order to attempt once more to acquire the needed knowledge.

I was reading an article a few weeks ago that laid out a plan for building a supergrid for North America. As part of that, they described and analyzed our existing transmission infrastructure. You might find it interesting. If I can turn it up, I'll post a link here, or a reference
That sounds like a pretty good idea; especially if by North American supergrid they encompass North-Eastern U.S as well as South-Eastern Canada, given the outages we've seen in that region in the past few decades. I didn't know that Japan had a 50Hz/60Hz split grid, what a headache; I wonder how/whether they're going to address that. Thanks for looking up your source doc on the supergrid, it definately sounds interesting.

You seem to be working on a particle theory for electricity. I'm wondering how it might work if you tried thinking of it as a wave instead.
Interesting. Looking back now I do realize that I rather am approaching this with the modal of particle theory in mind. I'll try to think of it as a wave at times to see if it helps.

You know, when you mention that we lose voltage across distance I recall encountering this concept when reading about wiring for solar panel and/or wind mill setups, and perhaps it's time for me to ask about what I find to be a very confusing aspect of electricity and that is Amperage VS voltage.

With our discussions and the info I've gathered so far in this forum I think I understand pretty well by now the concept of a coulomb, and that it is moving in a circuit in a given amount of time (one second) thus giving us Amperage.

I wish I had recieved a response yet from SeasOn following my response in post #9 because I asked him a few questions that I hoped would advance my knowledge of Voltage.

As it stands now for me, and following a lot of thinking in the past few days, I think I know what remains cloudy in my mind; it is the strange, obscure relationship that exists between Amperage and Votage.

Looking back, let me tell you how I first found this to be a difficulty without yet knowing exactly why: I was about to purchase a lot of 1.5 volt button batteries online and while shopping around I came accross what I thought was a pretty good deal for a lot of them. Now just before I clicked "purchase" I saw that there were user comments on those batteries so I decided to read them and at some point one person said that they had already purchased these batteries before and that even though they were replacing his original 1.5V thermometer batteries the new ones did not work.

So someone else replied that even though both his original and newly purchased batteries were 1.5V, they must have been of different amperage to account for his issue.

At that point they were talking about milliamps or milliamps per hour.

Finally, in between their conversation, they established that the batteries the website was selling had a lower mah than the more expensive ones you could buy from another site.

I was flabbergasted.

I thought all along that all I had to worry about in my every day life was voltage of my batteries and now I had to worry that with the wrong mah my batteries might not work for my application?

But even worse, I didn't understand why and I still don't.

I think one thing that would help is to run through my mind a couple similar scenarios of, say, a circuit powering an incadescent light, where in one scenario we have more volts and less amps, and in the other we have more amps and less volts.

Would you happen to have examples and the effects?

I think my question is still more vague than I'd like it to be but it's getting late and I'd like to post this to get the ball rolling. If I have more to add to my question I'll come back to it today and re-edit it or post a different question.

Thank you,

- Flood

 
  #15  
Old 05-13-12, 08:17 AM
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Looking back now I do realize that I rather am approaching this with the modal of particle theory in mind. I'll try to think of it as a wave at times to see if it helps.
Throughout this thread you've been posting about electrons moving through the circuit. The way I'm reading it, you may think that electrons move from a source to a destination. That isn't true. Although there is some physical movement of electrons (drift velocity), it is the energy that moves through the circuit. A wave of water, analogous to a circuit: The water moves slightly in the general direction of the wave, but the wave itself moves hundreds of times faster.

As for the relationship between volts and amps: It is directly proportional: P=IE where P=power (watts), I=current (amps), and E=voltage. A 60-watt light bulb will draw .5 amp at 120 volts.
 
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Old 05-13-12, 03:41 PM
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That sounds like a pretty good idea; especially if by North American supergrid they encompass North-Eastern U.S as well as South-Eastern Canada, given the outages we've seen in that region in the past few decades... Thanks for looking up your source doc on the supergrid, it definately sounds interesting.
Good news #1 is that I found the article. It's How to Build the Supergrid in the November 2010 issue of Scientific American. Good news #2 is that I found an online link to it. The bad news is 1> the online link is to a preview - you have to buy the issue to read the whole thing - and 2> it's only talking about the contiguous 48 states.

I'm going to re-read it because it talks at length about building high-voltage direct current trunks. I'd completely forgotten that, and it appears to knock my long-held belief that AC is a more efficient form for transmitting power on its ear.

perhaps it's time for me to ask about what I find to be a very confusing aspect of electricity and that is Amperage VS voltage.
I think Rick answered that.

I was about to purchase a lot of 1.5 volt button batteries online and... at some point one person said that they had already purchased these batteries before and that even though they were replacing his original 1.5V thermometer batteries the new ones did not work.

So someone else replied that even though both his original and newly purchased batteries were 1.5V, they must have been of different amperage to account for his issue.

At that point they were talking about milliamps or milliamps per hour.
I don't know what that was about. Batteries are rated for amp-hours or milliamp-hours relative to the amount of power they can deliver before being drained. That is not amps or milliamps per hour, and it should have no bearing on whether a battery will power a given load - only on how long it will power it.

I think one thing that would help is to run through my mind a couple similar scenarios of, say, a circuit powering an incadescent light, where in one scenario we have more volts and less amps, and in the other we have more amps and less volts.
See Rick's post.
 
  #17  
Old 05-13-12, 05:55 PM
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Sorry for being absent!! I believe (or trust) Nash has been doing a good job. (Note: I havenít read everything). Iíve decided to stand back. This topic can get very technical, and Iím not sure I have the time to explain. I will voice an opinion or two, if I see a reason too.
@flood,
based on reading some of what you wrote, I believe you are highly intelligent, and are above the basics. In many cases, Iím not sure electricians have to know as much as basic electrical theory. Itís the electrical engineers that get deeperóand this will depend on the task involved. Note: When I talk about electrical engineers, Iím talking about the electrical theory, or science of the electrical trade. Not the actual installation.
 
  #18  
Old 05-13-12, 07:26 PM
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Sorry for being absent!!
Welcome back! I missed your erudite voice here, and was just thinking of PMing you to suggest your return.

I believe (or trust) Nash has been doing a good job.
Thank you for your kind words.

Iíve decided to stand back. This topic can get very technical, and Iím not sure I have the time to explain. I will voice an opinion or two, if I see a reason to.
Understood.
 
  #19  
Old 05-13-12, 11:26 PM
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@ Nash,
TY

I normally add all the smiles because we have a minimum amount we ďmustĒ write.
 
  #20  
Old 05-14-12, 12:56 AM
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Hi Guys,

Thank you very much for your replies.

@Nashkat1 Thank you for looking up the article; I'm going to check it out later today and post more details when I get a quality minute.

@Rick Johnston Welcome to the discussion and @SeaOn welcome back!

I've got to prepare for a phone interview and get my weekday groove on but I've read your posts a couple of times tonight already, am mulling that over and will post a more detailed response later today.

Here's my icon contribution in the meantime!



- Flood
 
  #21  
Old 05-15-12, 02:49 AM
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@Rick Johnston

Alright Rick I've got to say... Your info about drift velocity is landing with a bang... And it's still making waves.

Nashkat1 did mention already that my looking at electricity from the point of view of electron movement wasn't helping my understanding.

I am quite dismayed because I thought I was real close to my hurrah moment. But now it feels like I'm in totally uncharted waters.


I've spend the last 3 hours or so all over Wikipedia and I've got more reading ahead.


But on drift velocity I read that with a DC current an electron ends up moving about 1 metre per hour and with AC current it isn't really going anywhere because of the back and forth effect. Summarizing what I've read so far across different pages there was talk of concepts such as electric fields, electromagnetism, wavelengths, phases, induction, propagation...


When I was just a kid I remember my dad and I watching a documentary and I remember him saying that scientists still didn't know what electricity really was. Not sure if that's the case now or even was the case back then.


At this point in my quest for understanding electricity some of the questions that I still have might actually be best answered by experts who are from a different field; like SeaOn pointed out. If I end up asking such questions then please let me know. For now I'm going to try to leave this aside. I say try because it keeps coming back, it seems, at every corner.


For example I read that in a battery-powered circuit electrons flow from one electrode to the other...


I also understand that there is certain amount of knowledge, as intimated by Furd, that is sufficient enough to build circuits and devices without having to bother with what is going on under the hood. I mean, I know, because when I finished my basement I did all the wiring myself.


I still have some questions that members of this forum may be able to answer.


I need to sort them out and formulate them better before I ask them though.


It's bedtime for me already.


I'm hoping to have something more concrete to ask this forum by the end of the day.


Thank you all for your input.




- Flood
 
  #22  
Old 05-15-12, 12:48 PM
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Just an edit here on my previous post that I no longer seem to be able to do for some reason.

I mentioned that Electrons are said to be moving about 1 meter per second.

The edit would be that they do so "in a copper wire of a certain gauge".

That piece of info from Wikipedia's take on Drift Velocity seems to indicate that there is a relationship between the density of the conductor (copper wire, in that case, and in moles) and the velocity of electrons.

In other words, if you change the conductor the electrons would move either faster or slower.

Actually, when moving through air, I read that it is close to the speed of light and that the length of one wave was about... 150 KMs or so; if I remember correctly. A.K.A. Fermi Velocity if I'm not mistaking.

But don't take my word for it because in that article there were other concepts coming into play that I might not be understanding/representing correctly here.

Cheers.

- Flood
 
  #23  
Old 05-15-12, 03:14 PM
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I mentioned that Electrons are said to be moving about 1 meter per second... That piece of info from Wikipedia's take on Drift Velocity seems to indicate that there is a relationship between the density of the conductor (copper wire, in that case, and in moles) and the velocity of electrons.
Side issue or distraction. If some electrons drift, so be it.

Getting the power from Point A to Point B does not rely on the physical dislocation of electrons. If it did, either the conductor would be destroyed in short order or we would never get a usable amount of power. It's the wave, not the particle.

Side note: Consulting Wikipedia may not be the most reliable way of getting solid information. On any subject.
 
  #24  
Old 05-17-12, 09:57 AM
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@Nashkat1 and @Rick Johnston

Thank you for your input.

I'm still finding a lot of information out there to the fact that, say in a battery-powered circuit, electrons are flowing from one pole to the other.

@Nashkat1

Remember the case of the button battery purchase that I recounted to you earlier? One person was saying that their 1.5 volt button battery wasn't able to power their thermometer, even though their original, 1.5v "stock" battery was able to just fine. You replied:

I don't know what that was about. Batteries are rated for amp-hours or milliamp-hours relative to the amount of power they can deliver before being drained. That is not amps or milliamps
per hour, and it should have no bearing on whether a battery will power a given load - only on how long it will power it.
Especially, I want to talk about the part where you say:

it should have no bearing on whether a battery will power a given load
Correct me if I'm wrong, but by "it" you mean the amperage as in mah; correct?

And you mean to say that different amperage, or current, will not vary the power output; correct?

If so I can't seem to be able to reconcile this with what I found in this youtube clip, and maybe you or another member can shed some light on this for me: Create a Lemon Battery - YouTube where the person mentions at around the 2:55 mark that his lemon "does not produce enough current to power this led". He then goes on to say "Higher voltage will move more current through the LED".

This seems to go against the fact that manufacturers are able to build batteries of the same voltage but that are able to provide more current.

As is the case here where manufacturers built certain 1.5V batteries at varying Milliamps Per Hour; such as, for example on this site: 1.5v Coin Cell Battery-1.5v Coin Cell Battery Manufacturers, Suppliers and Exporters on Alibaba.com the first displayed battery is rated as having a capacity of 13mah, while the third one is rated as having a capacity of 145mah.

If you or other members can explain the science behind that it would help me a lot.

My other question is sometimes we refer to the Amperage as capacity, sometimes as durability and sometimes as current.

At this point I am back to my question of a few days ago on post #14 where I ask:

I think one thing that would help is to run through my mind a couple similar scenarios of, say, a circuit powering an incandescent light, where in one scenario we have more volts and less amps, and in the other we have more amps and less volts.

Would anybody like to gave me a few scenarios to help me understand, in light of my info above, how varying voltage in relationship to different amperage, affects, say, capacity, durability and current, as it applies, say, to the circuit in the youtube lemon circuit clip mentioned above?

Once I have a better understanding of this I will tie this in to my understanding that 1 amp is 1 coulomb flowing through a circuit in 1 second.

Thank you,

- Flood
 

Last edited by Flood; 05-17-12 at 10:36 AM. Reason: Clarity
  #25  
Old 05-17-12, 01:33 PM
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Remember the case of the button battery purchase that I recounted to you earlier? One person was saying that their 1.5 volt button battery wasn't able to power their thermometer, even though their original, 1.5v "stock" battery was able to just fine. You replied:

I don't know what that was about. Batteries are rated for amp-hours or milliamp-hours relative to the amount of power they can deliver before being drained. That is not amps or milliamps
per hour, and it should have no bearing on whether a battery will power a given load - only on how long it will power it.
Especially, I want to talk about the part where you say:

it should have no bearing on whether a battery will power a given load
In this youtube clip: Create a Lemon Battery - YouTube the person mentions at around the 2:55 mark that his lemon "does not produce enough current to power his led". He then goes on to say "Higher voltage will move more current through the LED".
It's clear here that we were talking about the amp-hour rating of batteries in that discussion, not about voltage. If you want to switch from amps to volts, just use the formula Rick posted in #15.

To paraphrase what someone said recently in another thread here, a battery rated at 14 amp-hours can provide 1 amp for 14 hours or 14 amps for 1 hour before it is completely drained. (Not really, because the battery is probably designed to shut down when it gets down to 40% or so of full charge to prevent damage to it, but you get the idea.)

Electrical current is a measure of the amount of electrical charge transferred per unit time. This will come up again later.

Just to be clear, arguing or discussing material found on YouTube or Wikipedia does not help me meet my need to focus on meaningful information. Now if someone tells me that an authority in the field - I'll use Mike Holt as an example - has posted an interesting video on - oh, I don't know... let's say "stray voltage" - then I'll go watch it. But that's because Mike Holt is a leading authority on the National Electrical Code and all questions related to it, not because there's a cute new video among the millions already on YouTube.

Here's an analogy, for your questions about electrical current. Imagine that water is like electricity. It has no mass or other physical physical properties. It can't be seen, tasted, weighed heard or otherwise sensed. It's a force, IOW. It's energy. And imagine that we can generate it, put it through a conductor and use it to do some work, and we can control and measure its properties. In addition, in order to do that, we must connect our device directly to a supply pipe and a drain pipe.

In this very crude analogy, a coulomb is a (dimesionless) ounce of water, a copper pipe is the conductor and voltage is water pressure. The pipe does not react in any way in order to have the water do its thing. And the water is not consumed or lost in the process (note the complete closed circuit). So, when the combination of the water pressure and the nature of the device we connected - the load - are such that one ounce of water passes a point where we are measuring it in one second, or appears to pass that point, then we have one ounce/second of power, or one amp.

I told you it would come up again later.
 
  #26  
Old 05-17-12, 02:12 PM
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@Nashkat1 Thank you for your input. I've also had the analogy of electricity to water explained to me in the past.

If anybody else would like to comment it'd be greatly appreciated.

Summed up, inquiries I have are:

- Explanation into how batteries of same voltage can have different Amperage.
- Examples of output in simple battery-powered circuit where voltage and amp differ.
- Confirm/infirm whether higher voltage moves more current.
- Confirm/infirm whether in a battery there is actual movement/displacement of electrons; and whether it does so according to drift velocity.
- Any scientific explanation into how 2 batteries of same voltage, but of different mAh, could account for one successfully powering a device and the other not. Human error? Battery malfunction? Manufacturing defect?

Perhaps these inquiries should be their own thread.

If someone has other online resources to suggest that'd also be greatly appreciated as well.

Thank you,

- Flood
 
  #27  
Old 05-18-12, 06:17 AM
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- Explanation into how batteries of same voltage can have different Amperage.
Because they are manufactured that way. Not meaning to sound flippant, but battery design varies according to the intended use. Consider the very high amp-hours of a 12-volt deep cycle marine/RV battery versus a small lion used on the back of a camcorder.
- Examples of output in simple battery-powered circuit where voltage and amp differ.
A cooling fan inside a computer. The fan is rated at 2 watts. Under normal conditions it runs on 5 volts. 2 watts / 5 volts = .4 It is drawing 400 milliamps (.4 amps). When the computer gets hot the fan is switched to to the 12-volt supply. 2 watts / 12 volts = 166 milliamps.
- Confirm/infirm whether higher voltage moves more current.
Along the same wires? Yes. Just look up. Those high-voltage power transmission lines are carrying hundreds of thousands of volts -- enough to power a city. The voltage is stepped down by transformers at the distribution substations, and again at the transformers in our backyards. By the time the wires enter the house the voltage has been dropped to 240 volts, but the wires can carry 100 amps. So ... if your house has a 100-amp service at 240 volts, how many amps does that 500,000 volt transmission line need to handle? How many homes can be powered by that line?
- Confirm/infirm whether in a battery there is actual movement/displacement of electrons; and whether it does so according to drift velocity.
I cannot confirm this. I have never watched an electron. (Sorry -- that was flippant!) There may be some movement of electrons, but a battery produces energy via a chemical reaction.
- Any scientific explanation into how 2 batteries of same voltage, but of different mAh, could account for one successfully powering a device and the other not. Human error? Battery malfunction? Manufacturing defect?
One is rated to deliver the power required by the device. The other is not. If the device requires 200 mah and the battery is rated for 10 mah, the device may work just long enough to kill the battery.
 
  #28  
Old 05-18-12, 11:08 AM
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@Rick Johnston

Thank you very much for your responses. I'm going to be chewing on that for the next little while and let it sink in.

I'm might run my own lemon experiment too, maybe that'll help to understand things at that level; I do have a voltmeter so it'll be at least fun. In that youtube clip that I referred to in a previous post the gentleman ended up slicing his lemon in four to increase his voltage - my jaw dropped; I would have just added more lemons - and he was able to 'barely' power an LED... I got a kick out of that too.

I cannot confirm this. I have never watched an electron. (Sorry -- that was flippant!)
Ah no flippin' worries ... We're getting close though or might already be there. There was an article on Popular Science a few months ago about something like that; actually, I found the link for you:

Captured: The First-Ever Images of Atoms Moving Inside a Molecule | Popular Science

And about 8 years ago an IBM employee ended up writing the letters IBM using, I believe it was 12, electrons. He moved them individually using a Electron Tunneling Microscope that he said he was able to build out of parts he got at Radio Shack.

Thank you all for your input. I know that it's hard to understand why someone wouldn't understand electricity basics; heck, my 14 y/o kid understands it and actually ended up giving me quite a refresher.

And it's a good break from those Eetimes.com lunchtime readings.

But any input I receive along with being able to ask what may appear to be irrelevant questions without attracting judgement helps filling these weird gaps I seem to have; not counting that I've known for a while that I might just be having one of these weird, psychological blockages because I don't seem to have a problem understanding much, much more complicated concepts.

Imagine showing up for counseling with a lemon, a penny and a nail; laying on the sofa and saying "it all started when I was 12"... and ending with "if you give me a knife I'll lite you up an LED"

Cheers.

- Flood
 
  #29  
Old 05-18-12, 02:56 PM
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Thank you for your input. I've also had the analogy of electricity to water explained to me in the past.

If anybody else would like to comment it'd be greatly appreciated.
And how did you hear the analogy each time?

I think I'm hearing here that you didn't enjoy... maybe my tone? I can understand that. I was not in touch with my best self, because sources of misinformation set my teeth on edge. Wikipedia, in particular, has caused both financial and reputational harm to people I care about. I'll just leave it at that, apologize, and own up that it's my baggage and I'll try to carry it more lightly in the future. I'm really glad Rick stepped in with both his greater knowledge of details and his calmness.

I found this interesting:
In that youtube clip that I referred to in a previous post the gentleman ended up slicing his lemon in four to increase his voltage - my jaw dropped; I would have just added more lemons...
because I watched that video before commenting on it, and not only do I not remember his slicing up his lemon, I remember his adding more lemons. So I'm wondering if we're talking about the same video, or it's a memory glitch, or what.

BTW, the example I used of a video I'd stop to watch was actually based in reality. It's Mike Holt discusses Stray Voltage, if you're interested. Fair warning: you might want to make a pit stop and refill the coffee before settling in -- the video runs 1 hr. 34 min.
 
  #30  
Old 05-18-12, 09:33 PM
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@Nashkat1

Eh no worries there Nashkat1; if I can't take a bit of frustration and abrasion when sticking my neck out on the internet then there's always television I didn't want to press you with my inquiries because I thought you might have been just running out of rabbits to pull out of your hat for me and that's understandable.

After all, I'd know what it's like. There are some in this house who are still not able to use the remote to switch the TV from Cable mode to PC mode when we want to watch a movie. And I've showed them how to do it many, many times. The only thing I haven't tried is hypnosis.

I've very seldom posted in forums so I also thought that maybe there was a certain etiquette, beat, grove, culture etc particular to this forum that I perhaps wasn't following.

On the water analogy: I don't know how to explain it but I seem to not be able to pick up the similitudes for some reason and so probably because of my confusion I end up idling-out and losing the narrator really early on in the analogy.

On Wikipedia: It did get a rather bad reputation some time ago. Add to that the harm that you witnessed and I can understand your stance with regards to that site.

Luckily I tend to follow the good practice of keeping an eye open for the possibility that any info I come across, especially on the internet, may just not be completely accurate.

The lemon btw gets the chop at about the 6min mark in the youtube video, just before the end.

I just clicked on your link to Mike Holt's clip and I'll finish watching it when I get some quality time; the first few minutes look quite interesting; thanks for sharing.

It is due diligence that I massage and take-in the info you all shared with me in here this week before I post back with more questions, if any; so I will try to do that when I get a chance.

And I know I've said it before but I really do appreciate that you have taken the time to have a go at my inquiries.

Who knows, maybe it's that one innocuous little bit of info that will make the whole concept click for me.

Have a good weekend!

- Flood
 
  #31  
Old 05-18-12, 09:53 PM
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@Nashkat1 and @Rick Johnston

Speaking of information accuracy. I found more info on that IBM feat that I posted about and wanted to correct a few things I reported.

- It was a Scanning Tunneling Microscope that was used, not an Electron Tunneling Microscope.
- It was atoms that were individually moved and placed to form the IBM letters, not electrons.
- It happened in 1990, not 8 years ago. (Now how could I confused that?).
- He used 35, not 12 atoms.

And last but not least: (Drum roll please)

He did not actually build his Atom-moving machine with pieces from Radio Shack, what he said was that someone could probably build his own machine using pieces from Radio Shack.

There are many different kinds of articles out there with regards to this feat but I found one that has lots of info about that particular feat, as well as other related ones; and it does have photos too. It is available here:
20 Years of Moving Atoms, One by One | Gadget Lab | Wired.com


Cheers

- Flood
 
  #32  
Old 05-18-12, 10:04 PM
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I thought I remembered that story, but it was waaaaay hazy. Thanks for the memory jog and the link.
 
  #33  
Old 05-18-12, 10:21 PM
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Eh no worries there Nashkat1; if I can't take a bit of frustration and abrasion when sticking my neck out on the internet then there's always television
Great. Thank you.

On the water analogy: I don't know how to explain it but I seem to not be able to pick up the similitudes for some reason and so probably because of my confusion I end up idling-out and losing the narrator really early on in the analogy.
S'OK. I think the only really important part of it is that voltage is much like water pressure. It starts to break down pretty quickly after that.

The lemon btw gets the chop at about the 6min mark in the youtube video, just before the end.
OK. Cute. I thought I'd watched it all the way through the first time.

Additional evidence in support of Rick's point that "a battery produces energy via a chemical reaction."
 
  #34  
Old 05-21-12, 10:22 PM
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Hi guys,

Alright, I am very excited at the moment.

After an evening of watching a couple clips online "in slow mo" over and over again I think I may be understanding something about electricity at a certain level.

I'm attempting to test my newly acquired knowledge by running it through a scenario that I already had to deal with a few months back after buying a bunch of LEDs online that came with no specs, but that included a bunch of resistors.

When I received the kit I tried to determine the power draw (a.k.a. wattage, is that correct?) of the LEDs by having a simple circuit consisting of two 1.5 volt button cell batteries in series, my test LED and a resistor in between that I would interchange with other ones until I got most brightness without burning the LED; I was willing to sacrifice some LEDs in the process so that was no problem.

I then looked up the color codes of the resistors online and determined to the best of my abilities but with good confidence what the resistance value was. Is that how you call it: Resistance value?

So here's what I'm driving at. In one instance my test gave me this:

3v source, 170 Ohm resistor.

Questions for you:
1- Having learned tonight that P = Vsquare / R, is this the correct formula to use to determine the wattage of my LED in this case?

2- If so, then that LED looked like it could "safely" draw 3square / 170 or 9 / 170 or 0.0529 Watts; is this correct? If not then what's the correct formula to use here and why? This value looks like it makes absolutely no sense whatsoever to me BTW.

3- I've seen a lot of talk of mAh when talking about the power draw of an LED. Why would we talk of mAh instead of watts for an LED?

4- Why do we talk of watts for the power of an incandescent light bulb, and of mAh for an LED? (Inversely, why don't we talk of mAh for an incandescent bulb?)

5- In the circuit I've just described and using a voltmeter; if I check the voltage coming out of my batteries and it says 3v, and I then check the voltage coming out on the other side of my Resistor+LED combo, should I expect to get the same 3v? I'm asking because I still don't get that. In an earlier post I asked a similar question to Nashkat1 and the answer was that I should have the same number of electrons on the other side because the electrons used to do the work don't get "consumed". I'm still struggling with that, it doesn't seem to make some sense to me.

After writing all this my great moment is gone. I feel I have thoroughly reconfused myself trying to make sense of this.. It's so, so frustrating.

Anyways... Any pointers greatly appreciated.

Thank you,

- Flood
 

Last edited by Flood; 05-21-12 at 10:25 PM. Reason: Special characters not appearing correctly after posting.
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