Put t on the left side? Vc = V * (1- e^(-t / R*C))

[ljcox]

Bill,
I don't understand why you have exp(1)* rather than ln

And it is RC ln{1/(1 - Vc/V)}

 

[blueroomelectronics]

The "Just BASIC" compiler does not have an ln() statement.
exp(1) [2.71828183] seems to work fine, I'll remove the brackets.

 

[ericgibbs]

The "Just BASIC" compiler does not have an ln() statement.
exp(1) [2.71828183] seems to work fine, I'll remove the brackets.

Bill,
Some Basics consider the 'log' statement as meaning natural logs to base 'e'

Try 'print log(2.71828183)' you most likely get '1', this will confirm that your Basic considers 'log' as a natural log reference.== 'ln'

 

[eng1]

Bill,
Some Basics consider the 'log' statement as meaning natural logs to base 'e'

Eric, you're right. The manual of that compiler says:

LOG(n) Description:
This function returns the natural logarithm of n.

Usage:
print log( 7 ) produces: 1.9459101

BTW, it would be easy to get natural logarithm of x if you could use only base-10 logarithms:
ln (x) = 2.302585 * log10 (x)

 

[Hero999]

I never saw the point of the exp function, surly it's easier to do 2.71828183^x.

 

[tkbits]

Not really.

x ^ y where y is non-integer is calculated as base ^ (y * log-base x).

If base is 10, then x ^ y is 10 ^ (y log10 x). We used to do this with paper, pencil, and a table of logarithms.

If base is e, then x ^ y is e ^ (y log-e x), or exp(y * ln(x)). There are approximating polynomials for doing this on a computer.

 

[Papabravo]

The "ln" is an abreviation for "natural" or "Naperian" logarithms. Named after the Scottish mathemetician John Napier.

https://en.wikipedia.org/wiki/John_Napier