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What is Transconductance?
What is Transconductance?
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Old 16th November 2003, 06:37 PM   #1
Svetlana is offline Svetlana  New Zealand
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Question What is Transconductance?

What importance is this the Transconductance figure (Siemens) , in relatition to hexfets in hi-fi amps?
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Old 16th November 2003, 07:01 PM   #2
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Old 16th November 2003, 10:36 PM   #3
PMA is offline PMA  Europe
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What is Transconductance?
Ratio of output current change to input voltage change.
Gm=dId/dUgs
Id ... drain current
Ugs ... gate-source voltage
Gm ... transconductance
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Old 17th November 2003, 04:00 AM   #4
Nelson Pass is offline Nelson Pass  United States
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What is Transconductance?
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.
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Old 17th November 2003, 04:13 AM   #5
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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
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Old 17th November 2003, 04:14 AM   #6
Steve Eddy is offline Steve Eddy  United States
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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
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Old 17th November 2003, 04:19 AM   #7
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Default gimee mo...........................joe

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Old 17th November 2003, 04:39 AM   #8
Nelson Pass is offline Nelson Pass  United States
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What is Transconductance?
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.
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Old 17th November 2003, 04:48 AM   #9
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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
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Old 17th November 2003, 04:59 AM   #10
Steve Eddy is offline Steve Eddy  United States
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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
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