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RossW Guru Joined: 25/02/2006 Location: AustraliaPosts: 495
Posted: 04:14am 21 Jun 2010
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Probably still refers to capacitors as "Condensers" - a term which is very obsolete.
At the risk of sounding smug... this is what sh!ts me to tears... you've quoted something, MISUNDERSTOOD it, and are then trying to pound me over the head with it and you just can't see that you're wrong.
"Coulomb per second"
One Coulomb is 6x10^18 electrons per second.
So you have litterally
6x10^8 electrons / second
-------------------------
second
Basic maths shows that the seconds cancel.
Amps are not "amps per second".
Coulombs are electrons-per-second.
Amps are columbs-per-second
Do you GET IT?
I was ATTEMPTING to describe these basic units as YOU asked - in generic terms without making it silly-complicated for the average punter. You chose to WRONGLY introduce terms like "amps per second" which I tried to correct and it degenerated into a pissing match.
This is my last post on it. I'll spend MY efforts on things people appreciate. This isn't one, any more.
MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329
Posted: 05:20am 21 Jun 2010
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Well, there goes the ball game!
. . . . . Nothing difficult is ever easy!
Perhaps better stated in the words of Morgan Freeman,
"Where there is no struggle, there is no progress!"
Copeville, Texas
VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539
Posted: 06:08am 21 Jun 2010
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Oh Bugger
Looks like my book is obsolete and things have changed since I was a boy, my wife said I'm obsolete too, so as they say, you cant beat bad luck.
Sorry Mack and all if I have confused you with my ramblings.
I think I will go back to evicting white ants from the workshop.
And no my book doesn't refer to condensers in the definitions as it is capacitance and capacitors it talks about, but I call them condensers from force of habit, sorry about that, funny though a lot of tech books still refer to condensers.
I also looked in the latest TAFE electronics textbook and it defines a coulomb the same as my old book so they got wrong too.
All the best
BobEdited by VK4AYQ 2010-06-22Foolin Around
RossW Guru Joined: 25/02/2006 Location: AustraliaPosts: 495
Posted: 06:22am 21 Jun 2010
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Yup, you *really* don't get it.
The definition of a coulomb is fine.
The definition of an amp is fine.
YOUR ADDING "PER SECOND" to Amps is WRONG.
You love to (mis)quote your books, I invited you to show me any valid references to *AMPS per second* but you keep citing coulomb definitions. An amp is a coulomb per second!
Easiest way for me to stop replying to this waste of space is just not to read it either. Goodbye.
MacGyver your right, it is going all over the place.
Electrical theory and electronics really is a dark art For what it's worth:
(I hope I have this right, I'm sure it will be corrected if not)
RMS from what I remember is just the DC equivalent for the AC wave.
Hmmm if you think of the AC wave starting like an upside down U.
This starts from zero increases to a maximum and returns to zero.
To find out what the same DC steady state(eg voltage) is you take the average of it. This works out to be RMS (1 over root two times the peak if memory serves me)
Would be easier if current didn't flow backwards and forwards in a wire.
Maybe I should drag out my old Basic Electronics notes.Regards
Chris
Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333
Posted: 09:35am 21 Jun 2010
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Guys, if you are going to keep debating this, how about starting a new thread that is relevant to this topic.
Your idea is to help others, but here you are tacked onto another thread in an area that has little to do with what you are talking about.
How the heck is someone looking for information on this topic going to find the information here.
Pete.Sometimes it just works
Barry T Coles Senior Member Joined: 30/07/2009 Location: AustraliaPosts: 109
Posted: 10:32am 21 Jun 2010
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BINGOI need to learn from the mistakes of others.
I dont have the time to make them all myself.
Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333
Posted: 11:16am 21 Jun 2010
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Fine while its a current thread, but give it 6 months and then try to find it Barry.
To start with Solar is not the topic this belongs in, or you would search in for this information.
BINGO is Tuesday night at the CWA if thats what you are looking for.
Pete.Sometimes it just works
SSW_squall Senior Member Joined: 20/03/2010 Location: AustraliaPosts: 111
Posted: 04:00pm 21 Jun 2010
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Just a couple of further comments, to help understand some of the concepts mentioned
Mac:
An energy integral is just the area under a curve.
EG Power vs time graph , power on the vertical Y axis and time on the horizontal X axis.
A curve on this graph could be the power as generated by a wind turbine over time or the daily power useage of a household over time.
The ENERGY in kWh, either consumed or generated is simply the area under the curve...
It's same for RMS power, this is an integration as well, again just the area under the curve. Which is easy for sinewave AC with a resistive load where the voltage is in phase with the current, just divide the peak intantaneous power by 2 to get the RMS power.
However the rubber hits the road when you start talking about non-linear loads where the current waveform does is very peaky and not in phase with the voltage.
calculating the RMS power for this kind of load is not easy. That why true RMS meters are more expensive.
Bob:
You stated that XL = 2.PI.F.L whihc is fine, but called XL inductive resistance.
XL should be refered to as inductive reactance, similarly XC is capacitive reactance.
It may sound like symantics but the distinction is made so as not to confuse those resistive components which disipate real power whose current and voltage are in phase and those which don't consume real power whose voltage and current is out of phase by 90 deg.
Inductors and capacitors are fundementally defined by a differential equations (don't be scared)
For an inductor
V = L x di/dt
ie the voltage across an inductor is equal to the inductance times the rate of change of current with respect to time
(The formula XL = 2.PI.F.L can be generated from this differential equation by substituting a sinewave for the current and integrating)
Similarly for a capacitor
I = C x dv/dt
ie The current through a capacitor is equal to the capacitance times the rate of change of voltage with respect to time.
What does this have to do with reality??
Well quite abit actually...
Consider what happens when you switch on a fluroscent light:
1. The starter glows and the heat from the glow closes the contacts
2. Current flows through the ballast inductor, limited only by the filament resistance at each end of the tube.
3. Energy is stored in the magnetic field of the inductor
4. The starter contacts cool and open.
5. The rate of change of current is very high as the current flow stops very quickly.
6. According to the equation above the voltage across the ballast inductor is very high as the inductor gives up it's stored energy.
7. The voltage spike starts the discharge in the tube.
It's the same go for an ignition coil in a car, when the points (or now days transistor) opens.
For a capacitor, condsider what happens when you connect it directly to a battery:
The rate of change of voltage is very high as it jumps from 0 to 12v say in an instant, hence the current surges into a capacitor at a very high rate as it stores up energy.
I got drilled on this stuff for a couple of years doing my engineering degree and with good reason.
What happens when those relay contacts open?
What happens when power is applied and the capacitors are discharged?
Questions that are hard to answer without a good understanding of how resistors, inductors and capacitors behave...
That wasn't too hard??
AB
Einstein: Everything should be made as simple as possible, but not one bit simpler
VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539
Posted: 04:18pm 21 Jun 2010
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Hi SSW
I will have to go through your comments in the morning as brain dead at the moment.
Just a note though that the idea I had was to try to keep it reasonably simple for the ones without formal electronic training.
I did mine 45 years ago so am a bit rusty but know what to refer to in a book as they have a better memory than me, what I hoped was that those with skills would contribute a bit here and there to form a definitions for basic principles as related to our hobby not an electrical engineering course, that could be included later on as sections or chapters relating to specific subjects where added, the formula's I put in where there where as part of a discussion with Ross that got a bit out of hand and beyond the original terms of reference.
I have sent a draft copy to Pete and after he pulls it to pieces and hopefully corrects my mistakes I will throw it on again. Ross contributed a lot to it so its not just my work.
All the best
BobFoolin Around
MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329
Posted: 04:21pm 21 Jun 2010
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That wasn't too hard??
I think this is maybe why I became a plumber; we've only got 4 rules to worry about!
s*!t rolls downhill.
Payday is every day.
Keep your fingers out of your mouth.
If at first you don't succeed, use brute force!
See? Now that's more my idea of easy!
. . . . . MacNothing difficult is ever easy!
Perhaps better stated in the words of Morgan Freeman,
"Where there is no struggle, there is no progress!"
Copeville, Texas
VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539
Posted: 04:28pm 21 Jun 2010
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Hi Mack
I should have been a plumber but didn't like cleaning out septic tanks.
BobFoolin Around
MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329
Posted: 04:34pm 21 Jun 2010
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Bob
That used to bother me too, but once I figured out it was just "used food" it made working around stuff like that much easier.
It's just used food!
. . . . . MacNothing difficult is ever easy!
Perhaps better stated in the words of Morgan Freeman,
"Where there is no struggle, there is no progress!"
Copeville, Texas
grub Senior Member Joined: 27/11/2007 Location: AustraliaPosts: 169
Posted: 09:42pm 21 Jun 2010
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I remember seeing years ago about a company that made a joke documentry about refining excrement into reusable food. Made the end result look like a burger pattie. The gist of the joke was that there still was usable nutrient value in the excrement and by processing it to reclaim the said nutriment the end result could be reused as food again and again.
They had such a well thought out "docomentry" that industries even considered investing in the concept.
The jokesters all mimiced well known industries with similar products they produced but with outrageous ingredients/components.
MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329
Posted: 10:33pm 21 Jun 2010
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grub
I don't know about the joke documentary, but astronauts for sure drink their pee over and over. Just another reason not to be an astronaut, eh?
I think it's appropriate that you know about this recycled "food" stuff, seeing your 4m name is "grub"!
. . . . . Mac Nothing difficult is ever easy!
Perhaps better stated in the words of Morgan Freeman,
"Where there is no struggle, there is no progress!"
Copeville, Texas
VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539
Posted: 05:03am 22 Jun 2010
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Hi All
Ill leave it to the microbes and politicians, as it saves them thought to come up with their own, I know worms like too but not sure about Grub's.
Perhaps we could recycle politicians too if we could only find a way to purify the results.
All jokes aside my Uncle run a business cleaning septic tanks and composting the s==t on his farm, you should see the soil now, when you plant a tree you have to tie it down as it grows so fast in nearly jumps out of the ground.
Unfortunately he picked up a disease from it and it nearly killed him.
Enough s==t for now.
All the best
Bob Foolin Around
SSW_squall Senior Member Joined: 20/03/2010 Location: AustraliaPosts: 111
Posted: 08:20am 22 Jun 2010
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Hi Bob,
Yeah i take your point about keeping things simple...
I suppose i was just trying to point out that the calculus concepts of rate of change or the area under a curve are very much at the heart of any electronics.
Explaining these concepts in a visual or experimental way is actually more important and useful than a rigorous mathematical proof, because it means you can get to grips with the personality of the components in question.
There were plenty of people who did my course that could do the maths but didn't have the foggiest idea of how it applied to real world designs...
However it seems my attempts to put some thought into this thread is about as useful as nailing s**t to wall... hehe
ABEinstein: Everything should be made as simple as possible, but not one bit simpler
VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539
Posted: 05:13am 23 Jun 2010
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Hi SSW
No Problems mate and thanks for the input, as someone will read it and ask questions as an interest is the way to learn.
As with the power factor and inductance in AC circuits at this stage it was just to show they are there and do have some effect hope that will get the ball rolling in simple terms.
I agree that hands on is the best way to learn trouble is my arms are to short to help from here.
One of the problems I have with equations and formulas is that unless you understand all the terms thereof it doesn't make much sense, and to explain all the terms on here will be a major contract and boring to most except the math heads amongst us and they already know, so then pull the simple explanation apart and complicate it. Its a worry.
The other thing is I cant get my steam driven computer to do the formula's as laid out in the text books so they loose a lot of meaning without the proper layout, wish I could do maths with a hammer and screwdriver.
All the best
BobFoolin Around
Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1344
Posted: 07:38am 23 Jun 2010
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Just one thing to clarify since this thread is sofar off topic and the subject has turned to a No.2. In reality the trade of a 'plumber' should renamed to a 'Turd Surgeon' as 99% of the time thats their main job....
Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.
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