What is Transconductance?

Svetlana · 16th November 2003, 05:37 PM

What importance is this the Transconductance figure (Siemens) , in relatition to hexfets in hi-fi amps?

hitsware · 16th November 2003, 06:01 PM

http://whatis.techtarget.com/definit...214200,00.html

....

PMA · 16th November 2003, 09:36 PM

Ratio of output current change to input voltage change.
Gm=dId/dUgs
Id ... drain current
Ugs ... gate-source voltage
Gm ... transconductance

Nelson Pass · 17th November 2003, 03:00 AM

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.

hitsware · 17th November 2003, 03:13 AM

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

Steve Eddy · 17th November 2003, 03:14 AM

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

hitsware · 17th November 2003, 03:19 AM

.

Nelson Pass · 17th November 2003, 03:39 AM

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.

hitsware · 17th November 2003, 03:48 AM

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

Steve Eddy · 17th November 2003, 03:59 AM

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

16th November 2003, 05:37 PM	#1
Svetlana diyAudio Member Join Date: Oct 2003 Location: Christchurch	What is Transconductance? What importance is this the Transconductance figure (Siemens) , in relatition to hexfets in hi-fi amps?

17th November 2003, 03:19 AM	#7
hitsware diyAudio Member Join Date: Mar 2002	gimee mo...........................joe .

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

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?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	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

16th November 2003, 06:01 PM	#2
hitsware diyAudio Member Join Date: Mar 2002	http://whatis.techtarget.com/definit...214200,00.html ....

16th November 2003, 09:36 PM	#3
PMA diyAudio Member Join Date: Apr 2002 Location: Prague, Kitakyushu, Fukuoka	Ratio of output current change to input voltage change. Gm=dId/dUgs Id ... drain current Ugs ... gate-source voltage Gm ... transconductance

17th November 2003, 03:00 AM	#4
Nelson Pass The one and only 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.

17th November 2003, 03:39 AM	#8
Nelson Pass The one and only 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.