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Electronics => Beginners => Topic started by: orbiter on October 24, 2010, 03:07:34 pm

Title: Ohm's Law Triangle (Large)
Post by: orbiter on October 24, 2010, 03:07:34 pm
Was just looking on the net today at the many Ohm's Law triangles available and thinking.. How come there's not a large one out there so that noobs like myself can print a decent sized one out to stick on the wall? So for me, and people like me.. I made one :) Just click the link below to my Mediafire account for the large one...

(http://img.photobucket.com/albums/v146/orbiter/Ohms-Law-small.jpg)

http://www.mediafire.com/i/?xbhcaag51tt8jb4 (http://www.mediafire.com/i/?xbhcaag51tt8jb4)
Title: Re: Ohm's Law Triangle (Large)
Post by: Mechatrommer on October 24, 2010, 03:19:57 pm
very nice classic. maybe time for a new invention...
Title: Re: Ohm's Law Triangle (Large)
Post by: JohnS_AZ on October 24, 2010, 03:36:02 pm
Guess I'm showing my age, but it's odd to me to see the "V" in the triangle. I always learned it as "E" = IR.

And you're leaving out it's sister triangle...  P=IE  (or, I guess P=IV now-a-days).
Title: Re: Ohm's Law Triangle (Large)
Post by: Zero999 on October 24, 2010, 04:41:14 pm
Here's a better Ohm's law graphic. I admit I use this one. V = IR is easy and so is V = I2/R but I always have to work out the more obscure ones like V = ?(PR)
(http://www.reuk.co.uk/OtherImages/ohms-law.gif)
Title: Re: Ohm's Law Triangle (Large)
Post by: orbiter on October 24, 2010, 09:21:16 pm
Yea I think I saw that one too Hero, I like it. I'll probably do a large version of that too when I get a little more time.
Title: Re: Ohm's Law Triangle (Large)
Post by: Zero999 on October 24, 2010, 09:40:15 pm
Like this?
Title: Re: Ohm's Law Triangle (Large)
Post by: orbiter on October 24, 2010, 09:48:39 pm
I can't see it my friend :( Have you got a JPEG of it?
Title: Re: Ohm's Law Triangle (Large)
Post by: DJPhil on October 24, 2010, 10:20:03 pm
The ohm's law triangle is what I've had memorized since forever. I think to myself, "E over infrared" in order to remember it. It's goofy, but that's how I have to remember pretty much everything. It's not easy being cheesy.

I can't see it my friend :( Have you got a JPEG of it?
SVG files are great for printing large stuff, as they'll scale happily to any size without distortion. It's a good choice for this job!
There's an online converter here (http://www.fileformat.info/convert/image/svg2raster.htm) for converting them over, or you can use a program like Irfanview (http://www.irfanview.com) with the proper plugin (http://www.cadsofttools.com/download/irfanviewplugins.zip).

Hope that helps. :)
Title: Re: Ohm's Law Triangle (Large)
Post by: orbiter on October 24, 2010, 10:46:40 pm
Worked a treat.. Thanks DJ :)
Title: Re: Ohm's Law Triangle (Large)
Post by: scrat on October 25, 2010, 09:01:32 am
If one really needs a triangle to remember Ohm's law...
Why not adding the "capacitor's triangle" Q = C * V ? I found it very useful for easily obtaining capacitance behaviour.
If you derive it you get I = dQ/dt = C * dV/dt, if you want to know how much it will take to charge a certain capacitor at constant current (like a piece of MOSFET's gate charge) you make T = Q/I = C*V/I....
Title: Re: Ohm's Law Triangle (Large)
Post by: Zero999 on October 25, 2010, 05:09:32 pm
I can't see it my friend :( Have you got a JPEG of it?
Firstly you don't want to use JPEG for drawing, it's designed for photographs and will smudge line drawings. Use PNG format for drawings like this.

Secondly, if you're using any almost browser, except for Internet Explorer, you should be able to open it. If you see a message asking you what program to open it with, select Firefox, Chrome, Opera etc. and it should open up perfectly.

Finally, SVG can be read by many drawing programs. I use Inkscape.
Title: Re: Ohm's Law Triangle (Large)
Post by: orbiter on October 26, 2010, 11:53:49 pm
Firstly you don't want to use JPEG for drawing, it's designed for photographs and will smudge line drawings. Use PNG format for drawings like this.

Yea that was a mistake & force of habit I'm affraid as most of the stuff I do in CS5 needs to be saved as either TIFF's or JPEG's, and as I had loads of images ready for a batch process I just lumped my triangle in with them :o

Cheers though for poking me with a stick to remind me :)

orb
Title: Re: Ohm's Law Triangle (Large)
Post by: .o:0|O|0:o. on October 27, 2010, 12:19:07 am
I never understood the point of the triangle. If you really can't work out that a voltage results from a current passing through a resistor from first principles (say the analogy of pressure for water passing through a partially obstructed hose), then all you need to know is that V=IR, or "VIR", then chances are you know basic maths.

I remember when a teacher presented this to the class as some sort of revelation that would make life easier. I thought he was crazy!

The problem with the triangle is that you need to know Ohm's Law before you know what it is saying!

.o:0|O|0:o.
Title: Re: Ohm's Law Triangle (Large)
Post by: scrat on October 27, 2010, 09:06:20 am
I never understood the point of the triangle. If you really can't work out that a voltage results from a current passing through a resistor from first principles (say the analogy of pressure for water passing through a partially obstructed hose), then all you need to know is that V=IR, or "VIR", then chances are you know basic maths.

I remember when a teacher presented this to the class as some sort of revelation that would make life easier. I thought he was crazy!

The problem with the triangle is that you need to know Ohm's Law before you know what it is saying!

.o:0|O|0:o.

I must agree... Ohm's law is really simple, and I cannot figure out how one can deal with it if he doesn't understand (and then remember automatically) it.
Title: Re: Ohm's Law Triangle (Large)
Post by: orbiter on October 27, 2010, 10:32:01 am
Agreed.. It is really simple, once you know it. The point of the initial picture was for real beginners (I was one not too long ago) and so were you guys (maybe not so long ago :) ) The point of the initial 'larger' image was that anyone interested could just stick it on their wall for a short while just for referance, so that whilst doing their first projects (again like me) It would be easy to quickly check up on.

orb
Title: Re: Ohm's Law Triangle (Large)
Post by: Time on October 27, 2010, 04:46:47 pm
I've never seen this visual aid before and I don't really understand why it makes it easier to remember.  Its just a relationship that only has 3 variables...

Maybe it would be useful to have something for Maxwell's equations... or calculating inductance of solenoids and other things of this nature... but V=IR?  Come on!
Title: Re: Ohm's Law Triangle (Large)
Post by: orbiter on October 27, 2010, 05:40:50 pm
Jeez ya try and do something that maybe useful to somebody.
Title: Re: Ohm's Law Triangle (Large)
Post by: Time on October 27, 2010, 05:45:10 pm
Jeez ya try and do something that maybe useful to somebody.

Haha sorry, I wasn't trying to bring you down or anything.  Sorry for the troll moment.
Title: Re: Ohm's Law Triangle (Large)
Post by: orbiter on October 27, 2010, 06:03:10 pm
Haha sorry, I wasn't trying to bring you down or anything.  Sorry for the troll moment.

No worries mate ;)
Title: Re: Ohm's Law Triangle (Large)
Post by: Zero999 on October 28, 2010, 09:33:29 pm
I remember condensing all the simple formulae I needed for the whole GCSE science syllabus into three letter combinations like this. Yes, remembering VIR is the answer.