What is Transconductance? - diyAudio
Go Back   Home > Forums > Amplifiers > Pass Labs

Pass Labs This forum is dedicated to Pass Labs discussion.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 16th November 2003, 05:37 PM   #1
diyAudio Member
 
Join Date: Oct 2003
Location: Christchurch
Question What is Transconductance?

What importance is this the Transconductance figure (Siemens) , in relatition to hexfets in hi-fi amps?
  Reply With Quote
Old 16th November 2003, 06:01 PM   #2
diyAudio Member
 
Join Date: Mar 2002
http://whatis.techtarget.com/definit...214200,00.html

....
  Reply With Quote
Old 16th November 2003, 09:36 PM   #3
PMA is offline PMA  Europe
diyAudio Member
 
PMA's Avatar
 
Join Date: Apr 2002
Location: Prague
Ratio of output current change to input voltage change.
Gm=dId/dUgs
Id ... drain current
Ugs ... gate-source voltage
Gm ... transconductance
  Reply With Quote
Old 17th November 2003, 03:00 AM   #4
The one and only
 
Nelson Pass's Avatar
 
Join Date: Mar 2001
Even more simply:

If the transconductance is 1, then there is a 1 amp change
is Drain-Source Current for every 1 volt of Gate-Source
voltage change.

If the transconductance is 2, then there is a 2 amp change
is Drain-Source Current for every 2 volt of Gate-Source
voltage change.

and so on, this with transconductance expressed in Siemens,
which is the inverse of ohms.
  Reply With Quote
Old 17th November 2003, 03:13 AM   #5
diyAudio Member
 
Join Date: Mar 2002
Quote:
Originally posted by Nelson Pass
Even more simply:

If the transconductance is 1, then there is a 1 amp change
is Drain-Source Current for every 1 volt of Gate-Source
voltage change.

If the transconductance is 2, then there is a 2 amp change
is Drain-Source Current for every 2 volt of Gate-Source
voltage change.

and so on, this with transconductance expressed in Siemens,
which is the inverse of ohms.
Then all transconductances are = ?
I think if gm=2 then you get a 4amp change for 2volt change
  Reply With Quote
Old 17th November 2003, 03:14 AM   #6
diyAudio Member
 
Steve Eddy's Avatar
 
Join Date: Sep 2002
Location: Sacramento, CA
Quote:
Originally posted by Nelson Pass
and so on, this with transconductance expressed in Siemens,
which is the inverse of ohms.
Yeah, but Siemen sounds so... um... biological. I rather liked it when the unit really was the inverse of ohms; mhos. But alas, we've lost our mhojo.

se
  Reply With Quote
Old 17th November 2003, 03:19 AM   #7
diyAudio Member
 
Join Date: Mar 2002
Default gimee mo...........................joe

.
  Reply With Quote
Old 17th November 2003, 03:39 AM   #8
The one and only
 
Nelson Pass's Avatar
 
Join Date: Mar 2001
That's nothing. In the old days they granted the right of the
discoverer to name the element.

According to Cyclotronguy, this no longer exists, and in fact they
have renamed a number of the higher elements.

This probably explains why you don't see Kentium on the
periodic table of the elements.
  Reply With Quote
Old 17th November 2003, 03:48 AM   #9
diyAudio Member
 
Join Date: Mar 2002
Default i still think this ain't right

Quote:
Originally posted by Nelson Pass
Even more simply:

If the transconductance is 1, then there is a 1 amp change
is Drain-Source Current for every 1 volt of Gate-Source
voltage change.

If the transconductance is 2, then there is a 2 amp change
is Drain-Source Current for every 2 volt of Gate-Source
voltage change.

and so on, this with transconductance expressed in Siemens,
which is the inverse of ohms.
Disregarding paradyme shifts
  Reply With Quote
Old 17th November 2003, 03:59 AM   #10
diyAudio Member
 
Steve Eddy's Avatar
 
Join Date: Sep 2002
Location: Sacramento, CA
Quote:
Originally posted by Nelson Pass
That's nothing. In the old days they granted the right of the
discoverer to name the element.

According to Cyclotronguy, this no longer exists, and in fact they
have renamed a number of the higher elements.

This probably explains why you don't see Kentium on the
periodic table of the elements.
Hehehe. Yeah, but many of them are named after persons. Such as Lawrencium (after E. O. Lawrence), Nobelium (after Alfred Nobel), Mendelevium (after Dmitri Mendeleev), etc.

Guess we just have to wait 'til someone named Kent becomes worthy of such an honor.

se
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
ZV9 as transconductance amp we416b Pass Labs 15 4th April 2006 09:52 AM
Transconductance. lndm Tubes / Valves 16 18th March 2006 09:51 PM
A SOZ Transconductance Amplifier gl Pass Labs 21 16th December 2005 07:42 PM
Complementary Zen V.5 Transconductance Amp jbfitz Pass Labs 1 15th November 2005 08:27 PM


New To Site? Need Help?

All times are GMT. The time now is 01:55 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2