Ohm's Law sticky with LED section.

steveb

Joined Jul 3, 2008
2,436
The surprise I got here is that after the 30 page brawl on Electrotech, none of those guys spotted the error in fact!
So, I had to go over to electro-tech and see what happened. I see that you ran into Ratchit ! :eek: He used to be here under the name of Ratch. I assume he either got booted out of AAC, or finally just gave up harassing us and figured he could have more fun at electro-tech. Anyway, don't let him bother you. He really is hopelessly pedantic. He has many pet peeves including, this Ohm's Law definition, transitors being voltage controlled devices and the fact that it is wrong to say the current flows. He is like one of those slap-sticks http://www.youtube.com/watch?v=ULN7id0lmlA in the movie "Hitchhiker's Guide to the Galaxy". Every time you try to make a move, you get a wack when you least expect it.
 

MrChips

Joined Oct 2, 2009
30,720
(Two photons making an electron).

I saw this the first time I read it and wondered where you got that crazy idea.
I let it go.

But I think you should remove it.
 

Thread Starter

#12

Joined Nov 30, 2010
18,224
Done.

I vaguely remember picking up that idea while reading about fluorescent fixtures. Unfortunately, it was wrong. I wanted to explain why there are lots and lots of spare electrons laying about all over the place. I still don't know! Leftovers from the Big Bang? Strings having sex? Dr. Who spilled them?

Doesn't matter for a beginner.tut
Error corrected in the sticky in Chat.
 

Wendy

Joined Mar 24, 2008
23,415
Should be corrected in sticky period. I did it last night, but it took a bit to find the nuisance paragraph. Did I miss?

Ratch was determined to teach everyone the errors of the modern paragram of electricity. He would step in with beginners and begin explaining how everyone else was wrong and he was right. What he missed is they had to get the concepts down as it was written in their textbooks to pass their courses, some of the arguments had limited merit, but were off for people just beginning to learn the fundamentals. He was warned, but did it anyhow, and was banned as a troll.

He just couldn't help himself.
 
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Thread Starter

#12

Joined Nov 30, 2010
18,224
You did it right.
In post #35 of this thread you asked me to change the error.
In post #37 of this thread I described where I put the corrected verbiage.
The doubt for me is what you call the "master copy".
I believe the master copy is posts #18 and #19 of this thread.
That's why I put the correction in post #18 of this thread.

If you want to declare that the "master copy" is somewhere else, I will comply with your wishes.
 
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Wendy

Joined Mar 24, 2008
23,415
Naw, it's OK. I do ask you to highlight the changes though, it is a pain rereading things over and over.

Suggested change:

Is:
Electrons are real. They have weight and take up space, but they're really tiny! Electrons are so small that they actually sneak between the atoms in a copper wire. They are laying around, all over the place, by the millions. They are in the air, the water, and all throughout the solid mass of the Earth. We have plenty of them and we know where to find them. The job called, “electronics” is about how to use electrons to do stuff...useful stuff.
Could be:
Electrons are real. They have weight and take up space, but they're really tiny! Electrons are so small that they actually sneak between the atoms in a copper wire. They are laying around, all over the place, in numbers too large to easily count. They are in the air, the water, and all throughout the solid mass of the Earth. We have plenty of them and we know where to find them. The job called, “electronics” is about how to use electrons to do stuff...useful stuff.
I go through this all the time when I write. While I am not an expert, I do have lots of experience. You don't have to make the change, or use my suggested verbage (I probably wouldn't use my suggested verbage).

The reason I mentioned this is even with exponential system there tend to be a lot of zeros after any measurement of electrons, such as with current (1 ampere = 6.241 × 10^18 passing a point per second).
 

Thread Starter

#12

Joined Nov 30, 2010
18,224
Do you want me to put that, "in numbers too large to easily count" in post #18 of this thread?

I will if you want that. I also consent to you doing it.
Does it matter to you?
 
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Wendy

Joined Mar 24, 2008
23,415
Might as well keep the master copy accurate, the sticky will reflect it. Whilst I doubt it will change much, life has a way of forcing things on you sometimes. :)

The choice of verbage is totally yours.
 

Thread Starter

#12

Joined Nov 30, 2010
18,224
I put that phrase about "too large to count" in post#18 but I don't even know HOW to make it red!

Edit tag, you're it.
 
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MrChips

Joined Oct 2, 2009
30,720
I put that phrase about "too large to count" in post#18 but I don't even know HOW to make it red!

Edit tag, you're it.
Easy. Just go to the menu on the top of the Quick Reply message box and select the A menu item then choose the color you want.
 

Wendy

Joined Mar 24, 2008
23,415
Electrons are real. They have weight and take up space, but they're really tiny! Electrons are so small that they actually sneak between the atoms in a copper wire. They are laying around, all over the place, by the millions. They are in the air, the water, and all throughout the solid mass of the Earth, in numbers too large to easily count. We have plenty of them and we know where to find them. The job called, “electronics” is about how to use electrons to do stuff...useful stuff.
Not quite what I was talking about, but OK.

This is why highlighting is good.

Another useful editing button is this one, it shows all the editing features in their raw format. It was what I was referring to for transferring text verbatum, editing and all earlier in this thread. These are common features to VB, ElectroTech included.
 

Attachments

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strantor

Joined Oct 3, 2010
6,782
Isn't it funny when we can discuss delicate notions on electronics but can't understand each other in simple matters?
Isn't funny how after you made the comment, the misunderstandings continued to file in? I chuckle when I read this, makes me remember my grandmother trying to guide my grandfather backing a travel trailer down a long winding sandy driveway.
"ok, now go left"
"Ok, going left"
"NO! the other left!"
"What?"
"STOP! You're going to have to pull forward now and straighten up"..."ok, now come on back"..."ok, now sharp right"
"Ok, going right"
"NO, the other right!"
"God damnint Francis, get it straight, either YOUR RIGHT or MY RIGHT, Pick one, and stick with it!"
 

Thread Starter

#12

Joined Nov 30, 2010
18,224
When I go to post #18 and click on "Edit" there is no "Quick Reply" box.

When I go to post #18 and click on "Quote" there is still no "Quick reply" box.

For at least the third time, where is this Master Copy that I am supposed to be editing and what am I supposed to be starting with besides "edit"?
 
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Thread Starter

#12

Joined Nov 30, 2010
18,224
This is the box with a "Quick Reply" button. I clicked on it. It said , not enough characters. Now I'm typing.
Now I have clicked, "Go advanced".
I still don't see an "A" shaped symbol for font color.
Now I'm in "Preiview Post" and I still don't see the font color selection button,
I clicked on "Manage Attachments" and the is still no font color button.

Where is this "Master Copy" I am supposed to be replying to and where is the font color choosing button?
 

Thread Starter

#12

Joined Nov 30, 2010
18,224
Now I have gone to User CP and changed my setting to "Enhanced Interface".
Now I have a color button.
Where is the "Master Copy" I am supposed to be editing?
 

Thread Starter

#12

Joined Nov 30, 2010
18,224
Just about once a week, somebody posts a question like, “My boom box has a dead battery that says 12 volts, 1.8 amp-hours. The new battery says 12 volts, 2.4 amp-hours. Will the extra electricity burn up my radio?”

No, gentle reader, amp-hours are a measure of capacity. Your new battery has an extra quart of electricity, not a high pressure nozzle.

It's like standing next to a swimming pool with a glass of water. Water represents current and you represent the radio. You (the radio) can drink a glass of water (an amp of current) from either container, and no matter which one you choose to drink from, you are not going to drink the entire swimming pool and the swimming pool is not going to try to force you to drink it. You (the radio) only take as much as you need. Any properly working electrical device only takes what it needs. If that answers your question, good-bye. If you want to know why, keep reading.

The first thing you need to know about electricity is, “Don't touch it with your fingers, it bites.”
The second thing you need to know is Ohm's Law.

Ohm's Law is an equation.

The simplest equation in the world has 2 symbols and an equal sign.

1=1
2=2
number of jelly beans = 5

The next level is 3 symbols and an equal sign.

Distance = (miles per hour) x hours
inches = feet x 12
V=IR

That's as bad as it gets.

“V” means volts.
“I” means current, as measured in amps.
“R” means resistance...the resistance to the flow of electricity, and those resistance things are called ohms.

V=IR says, voltage equals current times resistance.
Sounds stupid at first.
How can you multiply current times resistance? There are no such things as amp-ohms!

Trust me. It works. Ohm's Law really says, “current equals voltage divided by resistance”. I=V/R
12 volts divided by 12 ohms is one amp. (V/R = I)

A 12 volt battery will push one amp through a 12 ohm radio, no matter if it's eight “D” cells connected in series or a 12 volt fork lift battery. That's because the radio has resistance.

In fact, any circuit that is working properly has resistance.

Getting a bit closer now...

Ohms are just ohms. However many ohms you have, the voltage will be divided by that number to find out how many amps will flow.

Volts are always volts as compared to some other place. That's why all volt meters have two wires. Volts are a unit of pressure, as in, how hard will the battery push on the ohms to get current through? Through to where? To the other end of the battery.

Amps aren't just lumps, like a pound of clay or a box of cookies. You can't have a box with an amp in it. An amp is a flow, defined as current per second. Like, water might flow in gallons per minute, but when you say, “amps” you are already saying, “per second” (literally, amp-seconds per second). When an amp flows for an hour, that's an amp-hour. You CAN have a box with amp-hours in it. It's usually called a battery. All the amp-hours don't come out of the battery at the same time. If they did, the battery would be empty in a millionth of a second. That's not very useful, is it? If your battery has 2.4 amp-hours in it, and you are using half an amp, the useful charge in the battery will last 4.8 hours.


How to get electrons to do useful work:

Electrons are real. They have weight and take up space, but they're really tiny! Electrons are so small that they actually sneak between the atoms in a copper wire. They are laying around, all over the place, by the millions. They are in the air, the water, and all throughout the solid mass of the Earth, in numbers too large to easily count. We have plenty of them and we know where to find them. The job called, “electronics” is about how to use electrons to do stuff...useful stuff.

The first thing to do is to get some electrons in a pile. Maybe that's why the first batteries were called, “piles”? (joke) Anyway, it is the difference in concentration of electrons that makes voltage. You see, electrons don't like each other. They “repel” each other. When you get a bunch of electrons in a pile, they want to leave, and the desire to leave is called, “voltage”. If you give electrons the opportunity, they will all scatter about until they are uniformly distributed. Any place that has more electrons than the nearest other place will find the electrons repelling each other and trying to become the same concentration of electrons per area, in all the areas that they can get to. That's where Ohm's Law becomes useful. When you let the electrons leave through a resistance, it takes time and they do work. If you make it complicated enough, it can be really interesting. For now, it's going to be a bit boring, but you have to start somewhere.

There are several ways to get a pile of electrons. Just walking across a carpet can scrape off enough electrons to make a spark. I don't know whether you scrape electrons off the carpet, or you scrape electrons off yourself, but it doesn't matter. It's the difference in concentration that makes voltage, and voltage makes sparks. The problem with this approach is that these electrons will try to escape to just about anywhere, and that isn't useful, unless maybe zapping your little brother is what you call useful. One of the reasons the electrons pile up is that air has a lot of resistance (ohms). Electrons don't flow through air like water does. They flow through air, and that's called lightening or static electricity, but it's not very useful.

Batteries cause electrons to pile up at the negative connector, and they want to leave, and at the same time, the chemicals in the battery reduce the concentration of electrons on the positive terminal, and that's where the electrons want to go...to the place with a less concentrated number of electrons. With a battery, you have two defined points that you can connect together through a device that has resistance and get a dependable flow to do something interesting or useful.

This is what Ohm's Law is about. Voltage divided by resistance equals amps. Amps times resistance will tell you the voltage that is driving the electrons per second through the resistance. If you know the volts by reading the label on the battery, and you can measure the amps with a meter, you can calculate the ohms that must be resisting the flow of electrons.

There are a lot of new words in this writing. You have to use the words until you begin to understand them. It takes time for your brain to make sense of this. You are allowed to read this as many times as you want to. We all go back and read stuff we have read before. Electronics is just too complicated to hold it all in your head, but Ohm's Law is small enough that you can learn it and keep it in your head. You will use Ohm's Law a dozen times a day when you are studying electronics, building a circuit, or fixing the brake lights on your pick-up truck. It's that important. You really must learn this in order to make any progress because there is no sub-section of electronics that does not use Ohm's Law.

<continued on next post>
This post #18 quoted and with red on the 7 words you wanted changed. Is this what you want?
 

Georacer

Joined Nov 25, 2009
5,182
Hello guys! I just returned home from a (merry?) weekend in the family olive tree fields.

I coloured the notorious phrase in the (master) post #18. I hope it's ok with you. I 'll do it if it's too hard for you. There is no sense sweating over technicalities.
 
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