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Old 23rd March 2013, 07:47 PM   #491
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Quote:
Originally Posted by stinius View Post
Of course it is not infinite, who has stated that?

U.S. Patent 3852678

BTW: the 1967 circuit is designed by Eckes.

Another great resource is Roy Gosser (ADI)

Stein
A voltage across a zero impedance gives infinite current....
My point was that the (low) input impedance of the inverting input does not determine the current into that node.

jan
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Old 23rd March 2013, 08:03 PM   #492
MiiB is offline MiiB  Denmark
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I see current feed back as current injected into a node between a CCS and the active device. If the device is feed by a resistor, things become more defuse as the current swing will also alter the voltage at that node. and you have a mixture. If feed back is applied through a BJT or af Fet, it'll be purely voltage feedback. To me current feedback is an additive process into the line of the driving current.
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Old 23rd March 2013, 08:30 PM   #493
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Quote:
Originally Posted by michaelkiwanuka View Post
There are plenty of so-called "CFAs" manufactured by the IC industry that do not use current mirrors.
That would be hard to prove. Produce a list?
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Old 23rd March 2013, 08:34 PM   #494
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Quote:
Originally Posted by stinius View Post
Another great resource is Roy Gosser (ADI)

Stein
Roy is a good buddy for the last 25 or so yr. He has his own style an interestingly different spin on this. His extra stage on the classic CFA has made a great difference.
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Old 23rd March 2013, 08:39 PM   #495
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Quote:
Originally Posted by scott wurcer View Post
That would be hard to prove. Produce a list?

LH4117

LH4118

LH4200
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Old 23rd March 2013, 09:43 PM   #496
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Quote:
Originally Posted by michaelkiwanuka View Post
LH4200
"Series feedback may be provided for gain stabilisation and input impedance improvement".
Exactly!

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Old 23rd March 2013, 11:50 PM   #497
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Old 24th March 2013, 12:35 AM   #498
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Quote:
Originally Posted by michaelkiwanuka View Post
LH4117

LH4118

LH4200
These are a real stretch as mainstream products, you should do better. This is a joke yes?
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Old 24th March 2013, 01:51 AM   #499
Bonsai is offline Bonsai  Taiwan
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Michael Kiwanuka wrote

"1) For a voltage feedback amplifier, the transfer function of the foward path is Voltage/Voltage.

2) For a transimpedance amplifier, the transfer function of the forward path is Voltage/Current.

3) For a transadmittance amplifier, the transfer function of the forward path is Current/Voltage.

4) For a current amplifier, the transfer function of the forward path is Current/Current."





Michael, you have COMPLETELY missed the point!

50 pages of posts and you are still banging on about the forward path!
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Old 24th March 2013, 01:56 AM   #500
Bonsai is offline Bonsai  Taiwan
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Natsemi hybrids IIRC?
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