FreeLists / si-list / [SI-LIST] Re: RC time constant question

[Raymond.Leung@xxxxxxxxxxx]

I still remember this question as one of my first year student
homework.

Since the fall time expression of an RC network is

V = Vo exp**(-t/tou)   where tou = RC

Therefore

t0.9 = -tou * ln(0.9); and
t0.1 = -tou * ln(0.1)

fall time = t0.1 - t0.9 = tou ( ln (0.9) - ln (0.1)) = 2.2tou or = 2.2RC

Similar expression could be obtained for rise time.

Regards,
Raymond






nagaraj <nagaup1@xxxxxxxxx> on 05/05/2005 21:30:34

Please respond to nagaup1@xxxxxxxxx

To:   SI_queries SI_queries <si-list@xxxxxxxxxxxxx>, si_steve_weir si_steve_weir
      <weirsp@xxxxxxxxxx>
cc:    (bcc: Raymond Leung/sdc)

Subject:  [SI-LIST] RC time constant question



Hi all,

I studied that the risetime  (10%-90%) for square wave  on RC network is equal
to 2.2RC

Can any one brief me on this .

Regards,
Nagaraj.

---------------------------------





------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field

or to administer your membership from a web page, go to:
http://www.freelists.org/webpage/si-list

For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field

List FAQ wiki page is located at:
                http://si-list.org/wiki/wiki.pl?Si-List_FAQ

List technical documents are available at:
                http://www.si-list.org

List archives are viewable at:     
                http://www.freelists.org/archives/si-list
or at our remote archives:
                http://groups.yahoo.com/group/si-list/messages
Old (prior to June 6, 2001) list archives are viewable at:
                http://www.qsl.net/wb6tpu