I need formulas explaining Voltage and Amperage

[russ_watters]

sorry russ, i felt like I am arguing against MrSparkle, i never meant it on you or anything else... I am glad for all the help, I am just new, and i don't socialize well which I appologize for behaving like a child...

It's ok - you've been upfront about that, so it's fine.

 

[NitroX]

so confused, what do you mean by upfront?

 

[russ_watters]

so confused, what do you mean by upfront?

You have been honest and we appreciate it.

 

[psparky]

Dear Nitro, I scribbled up this 4 page word document a couple years ago.

Give it a quick read...it's electrical terms put in Layman's terms.

Maybe it will help. Maybe it wont. See attached.

 

[NitroX]

do you have an older version of the document, you can do a save as on your document add .rtf at the end and i can look at it? thank u!

 

[NitroX]

If you want to teach yourself, you are going about it the wrong way. Grab a textbook, read it, and understand the concepts behind the formulas. Then you'll understand how to apply the formulas. If you have questions, then you come and ask. Then work through the problems so you know you understand both the concepts and the formulas and the math. We could give you all the formulas in the world, but that wouldn't stop you from misapplying them. As it is, it sounds like you are trying to break the law of conservation of energy. Well... good luck with that.

But since you asked, the basic equation for an inductor is v = L*(di/dt), and a good page for exponential decay is http://www.allaboutcircuits.com/vol_1/chpt_16/4.html.

heres a problem, is there a way to REVERSE the formulas to show decay rather than charging, yes htis is useful, but i need decay too.

 

[Born2bwire]

heres a problem, is there a way to REVERSE the formulas to show decay rather than charging, yes htis is useful, but i need decay too.

It's all apiece, the decay is simply the inverse behavior of the charge. You simply do the same derivation but you change the initial and steady-state conditions to reflect this. The time constants stay the same regardless. Those are only dependent upon the inductance and resistance of the system (barring any capacitive elements).

 

[NitroX]

hopw do i rewite the formula, canu give me an example please?

 

[Born2bwire]

It's given in the Wikipedia article on RL circuits. If you have a steady state RL circuit and turn off the applied voltage, then the decay is simply $I(t) = I_0e^{-\frac{t}{\tau}}$ since this obviously satisfies the initial condition of the current $I_0$ and the steady state condition of zero current.

 

[NitroX]

thank u so much! i will use that and study it!