Author Topic: Happy PI day (a day late) and a question  (Read 1157 times)

0 Members and 1 Guest are viewing this topic.

Offline dsharp02

  • Contributor
  • Posts: 26
  • Country: us
Happy PI day (a day late) and a question
« on: March 16, 2016, 02:58:14 am »
Was reading this:  http://tauday.com/

and it got me thinking about RC time constants and how tau is used as a shorthand.

If the Tau-ists had their way calculating cutoff frequencies for RC filters could get really confusing.

Fc = 1 / (2 * pi * R * C)
(substituting tau, the RC time constant) =>   Fc = 1 / (2 * pi * tau)
(substituting tau, the mathematical constant) => Fc = 1 / ( _tau_ * tau)

So I guess the question is tau? or pi?

 :popcorn:

 

Online ericloewe

  • Supporter
  • ****
  • Posts: 74
  • Country: pt
Re: Happy PI day (a day late) and a question
« Reply #1 on: March 16, 2016, 05:01:54 am »
Silly answer:

Pau = 1.5 * pi is the way to go. It'll please nobody, so nobody will feel left out.

Proper answer:

Notice how next to nothing is abbreviated with the letter pi. Since pi has been the traditional constant used, everything else more or less decided not to use the letter pi. Had tau been the "one true constant", I'd expect the opposite to happen - the letter tau practically reserved for 2pi and the letter pi more or less free to use in most contexts.
 

Offline TimFox

  • Frequent Contributor
  • **
  • Posts: 837
  • Country: us
  • Retired, now restoring antique test equipment
Re: Happy PI day (a day late) and a question
« Reply #2 on: March 16, 2016, 08:19:01 am »
I like "pi" because of the Euler equation: [ e ^ (i pi) ] + 1 = 0.
This simple equation contains e, i,  pi, 1, and 0 -- truly fundamental constants.
 

Online IanB

  • Super Contributor
  • ***
  • Posts: 8702
  • Country: us
Re: Happy PI day (a day late) and a question
« Reply #3 on: March 16, 2016, 08:30:10 am »
It only needs one sign change: \$e^{i\tau} - 1 = 0\$
I'm not an EE--what am I doing here?
 

Online ericloewe

  • Supporter
  • ****
  • Posts: 74
  • Country: pt
Re: Happy PI day (a day late) and a question
« Reply #4 on: March 16, 2016, 08:42:37 am »
Congratulations. You just proved that "pi vs tau" is an equivalent(ly silly) discussion to "plus vs minus".
 

Online Cerebus

  • Super Contributor
  • ***
  • Posts: 2817
  • Country: gb
Re: Happy PI day (a day late) and a question
« Reply #5 on: March 18, 2016, 10:40:46 am »
I like "pi" because of the Euler equation: [ e ^ (i pi) ] + 1 = 0.
This simple equation contains e, i,  pi, 1, and 0 -- truly fundamental constants.

So, we have pi day. Why not "e day" and "i day"? The latter I propose belongs on the 29th of February.
Anybody got a syringe I can use to squeeze the magic smoke back into this?
 

Online ericloewe

  • Supporter
  • ****
  • Posts: 74
  • Country: pt
Re: Happy PI day (a day late) and a question
« Reply #6 on: March 18, 2016, 11:01:45 pm »
I like "pi" because of the Euler equation: [ e ^ (i pi) ] + 1 = 0.
This simple equation contains e, i,  pi, 1, and 0 -- truly fundamental constants.

So, we have pi day. Why not "e day" and "i day"? The latter I propose belongs on the 29th of February.

Because it only happens once every four pi/2?
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf