Understanding the Formula for Exponential Decay of Voltage

[bryanehli]

Please Help!

This is based on the time at any point on the curve during exponential decay of voltage.

Could someone explain to me this formula?

t=T1n(E/Vl)

example:

t=(7.5ms)1n(20v/14.57v)=2.38ms.

I get 20/14.57=1.372683596
(7.5)(1.372683596)=10.29512697
where and how do you get 2.38, where does the 1n fall in and how? is there a numerical value for this statement? Please help?

 

[berkeman]

Please don't multiple post the same question. Your question was answered in your original thread:

https://www.physicsforums.com/showthread.php?t=237561

What you are writing as 1n is actually LN, or the natural log. It is a button on your scientific calculator.

 

[bryanehli]

it still does not work!

 

[berkeman]

it still does not work!

Yes it does.

t=(7.5ms) * LN(20v/14.57v) = 2.38ms.

Divide 20/14.57, take the natural log, then multiply by 7.5. I get 2.375something.

 

[bryanehli]

Thank You!