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Ohm’s Law Trick

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Forum Name: General Discussion
Forum Discription: General Mobile Electronics Questions and Answers
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=45434
Printed Date: May 10, 2024 at 7:04 AM


Topic: Ohm’s Law Trick

Posted By: Master Asylum
Subject: Ohm’s Law Trick
Date Posted: December 17, 2004 at 3:50 PM

This requires a basic understand of math(duh) and such. This may not really matter to anyone, but this system seems to be a really good way for my brain to remember all 12 equations off of 1 basis. (And it requires little thinking it out for those that aren't super smart in formula changes.)

The four basic formulas to remember:

I=E/R      I=P/E     I=Sq. Rt. of P/R       I=Sq. Rt. of P*R
(I find these really easy to remember since the first three are all division and barely alter[consistency] and the last on is a symbol change of its mirror.)

Now from here you can work out each formula to isolate the two symbols very easily. (If you can isolate easily this probably isn't much except maybe a decent formula memorization.)

For I=E/R; Move the E to the left portion, move I to the right portion (E=R*I). Now Move R to the left portion, E to the left side of the right portion of the equation and change symbol. Yes this is basic isolating, but if you do it in a table like shown below the 2 other base division formulas are plugin. All you have to do is take from the base equation and match up in coordination with the previously modified equations.

I=E/R, E=R*I, R=E/I
I=P/E, P=E*I, E=P/I
I=SqRt P/R, P=R*I^2, R= P/I^2 
I=SqRt P*R, P=E^2/R, R=E^2/P

(Note on square roots, if you DON'T know, squaring the entire equation cancels out the square root[they are ugly, let them die] and squares the other side of the equation. Ex. I=SqRt P/R would look like I^2=P/R)

Ok I don't know if this would really help anyone other than me, but honestly I have trouble with formula memorizing and I found a way to plug in things to help me figure it out. This may be just as much work(This isn't necessarily a shortcut) but it provides a different way to look at it, and some people need it. LMK on any insight please.



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1998 Monte Carlo w/
Eclipse CD8454
2xRockford 5.25" Power 2-way T152C
2xRockford 6"x9" Punch 3-way FRC4369
1xMemphis 16-MCH1300 5-channel
2xKicker 12" L5 Solobaric-2 Ohm



Replies:

Posted By: ~AFAccord~
Date Posted: December 18, 2004 at 3:26 AM

Not sure if this helps, but it's a nice little trick I learned in my Air Force tech school.   It's very simple to remember the basic equations.  For what ever value you're looking for, "cross" it out and you're left with the formula.  See the example to find Current (I).

posted_image

After you "cross" out the I, you are left with E over R or E/R.

posted_image

If this helps at least one person then my time in MS Paint will be well worth the effort. LOL



-------------
Black Cherry
"Experience is something you never get until just after you need it."




Posted By: stevdart
Date Posted: December 18, 2004 at 8:09 AM
Both posts above ambitious efforts and well done.  They help me to remember, that's a fact.  The first one is tougher for me to get because I remember pictures and symbols easier than words and numbers.  The second post with the triangle, I'll be using from this day on.




Posted By: Master Asylum
Date Posted: December 20, 2004 at 8:12 AM

Yeah, I'm a picture kinda guy too, I just was on a time crunch when I made that post. (Little break through with like 10 mins before work.) I'll try and get the chart up here later or something. (I have no where to put the picture either, so meh.) But that graphic does work nicely for the 3 basics. What about when you wanna venture into power? That's the only reason I really worked into a 4x3 chart design, is a way to cover all 12 equations on a small basis. (I really like that chart for remembering the 3/4 I need to.)



-------------
1998 Monte Carlo w/
Eclipse CD8454
2xRockford 5.25" Power 2-way T152C
2xRockford 6"x9" Punch 3-way FRC4369
1xMemphis 16-MCH1300 5-channel
2xKicker 12" L5 Solobaric-2 Ohm




Posted By: flynntech
Date Posted: December 20, 2004 at 6:20 PM
That's cool, I did something similar to remember the the power formulas for the MECP test. If you know how your brain best recognizes things, just stick with it. Jot it down right away when you take the test.





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