Forums

Op-amp Summing Amplifier

Started by Patrick Chung March 16, 2015
Good feature of op-amp summing amplifier is that there is direct current path provided from every input to the output. For that reasons input voltage sources don't need to have current sink capability.
Good feature of op-amp non inverting summing amplifier is that output voltage is proportional with the sum of the input signals, and with the same sign. Bad feature is that there is no direct current path from the inputs to the output, so input voltage sources must have sinking current capability. 

Read more:

http://www.cirvirlab.com/index.php/tutorials/172-op-amp-summing-amplifier.html

and also simulate:

http://www.cirvirlab.com/simulation/op-amp-summing-amplifier-online.php
http://www.cirvirlab.com/simulation/op-amp-non-inverting-summing-amplifier-online.php
Patrick Chung wrote:
> Good feature of op-amp summing amplifier is that there is direct current path provided from every input to the output. For that reasons input voltage sources don't need to have current sink capability. > Good feature of op-amp non inverting summing amplifier is that output voltage is proportional with the sum of the input signals, and with the same sign. Bad feature is that there is no direct current path from the inputs to the output, so input voltage sources must have sinking current capability. > > Read more: > > http://www.cirvirlab.com/index.php/tutorials/172-op-amp-summing-amplifier.html > > and also simulate: > > http://www.cirvirlab.com/simulation/op-amp-summing-amplifier-online.php > http://www.cirvirlab.com/simulation/op-amp-non-inverting-summing-amplifier-online.php
Yawn....
On 16-Mar-15 4:43 PM, Robert Baer wrote:
> Patrick Chung wrote: >> Good feature of op-amp summing amplifier is that there is direct >> current path provided from every input to the output. For that reasons >> input voltage sources don't need to have current sink capability. >> Good feature of op-amp non inverting summing amplifier is that output >> voltage is proportional with the sum of the input signals, and with >> the same sign. Bad feature is that there is no direct current path >> from the inputs to the output, so input voltage sources must have >> sinking current capability. >> >> Read more: >> >> http://www.cirvirlab.com/index.php/tutorials/172-op-amp-summing-amplifier.html >> >> >> and also simulate: >> >> http://www.cirvirlab.com/simulation/op-amp-summing-amplifier-online.php >> http://www.cirvirlab.com/simulation/op-amp-non-inverting-summing-amplifier-online.php >> > Yawn....
Fair go, it might be yawn for you but it may be useful for others. Why not have a look and point out any errors if you spot them?
On Mon, 16 Mar 2015 17:39:17 +0800, McAvity <slider123@ebul.com>
wrote:

>On 16-Mar-15 4:43 PM, Robert Baer wrote: >> Patrick Chung wrote: >>> Good feature of op-amp summing amplifier is that there is direct >>> current path provided from every input to the output. For that reasons >>> input voltage sources don't need to have current sink capability. >>> Good feature of op-amp non inverting summing amplifier is that output >>> voltage is proportional with the sum of the input signals, and with >>> the same sign. Bad feature is that there is no direct current path >>> from the inputs to the output, so input voltage sources must have >>> sinking current capability. >>> >>> Read more: >>> >>> http://www.cirvirlab.com/index.php/tutorials/172-op-amp-summing-amplifier.html >>> >>> >>> and also simulate: >>> >>> http://www.cirvirlab.com/simulation/op-amp-summing-amplifier-online.php >>> http://www.cirvirlab.com/simulation/op-amp-non-inverting-summing-amplifier-online.php >>> >> Yawn.... > > >Fair go, it might be yawn for you but it may be useful for others. > >Why not have a look and point out any errors if you spot them?
Chung is a spammer, out to make money. He posts trivial, borderline correct stuff. -- John Larkin Highland Technology, Inc picosecond timing laser drivers and controllers jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
John Larkin wrote...
> McAvity wrote: >> Robert Baer wrote: >>> Patrick Chung wrote: >>>> Good feature of op-amp summing amplifier is that there is direct >>>> current path provided from every input to the output. For that reasons >>>> input voltage sources don't need to have current sink capability. >>>> Good feature of op-amp non inverting summing amplifier is that output >>>> voltage is proportional with the sum of the input signals, and with >>>> the same sign. Bad feature is that there is no direct current path >>>> from the inputs to the output, so input voltage sources must have >>>> sinking current capability. ... >>>> >>> Yawn.... >> >> Fair go, it might be yawn for you but it may be useful for others. >> Why not have a look and point out any errors if you spot them? > > Chung is a spammer, out to make money. He posts trivial, > borderline correct stuff.
Yes, borderline correct, and actually, incorrect. For example, in this case he's arguing the summing junction pulls down and provides a current sink. However, that only holds true for positive signals, with summing junction at ground. Evidently Chung discounts the possibility of negative signals. But oops, an inverting configuration gives a negative output signal. To fix this, we use a single-supply configuration, raising the summing junction above ground. At this point Chung's claim, not very useful to begin with, is simply false. We won't waste time on his non-inverting arguments. -- Thanks, - Win
On Monday, March 16, 2015 at 10:14:15 AM UTC-4, John Larkin wrote:
> On Mon, 16 Mar 2015 17:39:17 +0800, McAvity <slider123@ebul.com> > wrote: > > >On 16-Mar-15 4:43 PM, Robert Baer wrote: > >> Patrick Chung wrote: > >>> Good feature of op-amp summing amplifier is that there is direct > >>> current path provided from every input to the output. For that reasons > >>> input voltage sources don't need to have current sink capability. > >>> Good feature of op-amp non inverting summing amplifier is that output > >>> voltage is proportional with the sum of the input signals, and with > >>> the same sign. Bad feature is that there is no direct current path > >>> from the inputs to the output, so input voltage sources must have > >>> sinking current capability. > >>> > >>> Read more: > >>> > >>> http://www.cirvirlab.com/index.php/tutorials/172-op-amp-summing-amplifier.html > >>> > >>> > >>> and also simulate: > >>> > >>> http://www.cirvirlab.com/simulation/op-amp-summing-amplifier-online.php > >>> http://www.cirvirlab.com/simulation/op-amp-non-inverting-summing-amplifier-online.php > >>> > >> Yawn.... > > > > > >Fair go, it might be yawn for you but it may be useful for others. > > > >Why not have a look and point out any errors if you spot them? > > Chung is a spammer, out to make money. He posts trivial, borderline > correct stuff. > >
He's a Serbian trying to make some change on the side, give him a break!
> -- > > John Larkin Highland Technology, Inc > picosecond timing laser drivers and controllers > > jlarkin att highlandtechnology dott com > http://www.highlandtechnology.com
On Tuesday, March 17, 2015 at 1:08:23 PM UTC-4, bloggs.fred...@gmail.com wrote:
> On Monday, March 16, 2015 at 10:14:15 AM UTC-4, John Larkin wrote: > > On Mon, 16 Mar 2015 17:39:17 +0800, McAvity <slider123@ebul.com> > > wrote: > > > > >On 16-Mar-15 4:43 PM, Robert Baer wrote: > > >> Patrick Chung wrote: > > >>> Good feature of op-amp summing amplifier is that there is direct > > >>> current path provided from every input to the output. For that reasons > > >>> input voltage sources don't need to have current sink capability. > > >>> Good feature of op-amp non inverting summing amplifier is that output > > >>> voltage is proportional with the sum of the input signals, and with > > >>> the same sign. Bad feature is that there is no direct current path > > >>> from the inputs to the output, so input voltage sources must have > > >>> sinking current capability. > > >>> > > >>> Read more: > > >>> > > >>> http://www.cirvirlab.com/index.php/tutorials/172-op-amp-summing-amplifier.html > > >>> > > >>> > > >>> and also simulate: > > >>> > > >>> http://www.cirvirlab.com/simulation/op-amp-summing-amplifier-online.php > > >>> http://www.cirvirlab.com/simulation/op-amp-non-inverting-summing-amplifier-online.php > > >>> > > >> Yawn.... > > > > > > > > >Fair go, it might be yawn for you but it may be useful for others. > > > > > >Why not have a look and point out any errors if you spot them? > > > > Chung is a spammer, out to make money. He posts trivial, borderline > > correct stuff. > > > > > > He's a Serbian trying to make some change on the side, give him a break!
Huh? I don't mind him posting links to his web pages.. I guess what bothers me is that he doesn't respond to any of the input/ feedback that he gets from us. He's ignoring a chance to improve his web site. George H.
> > > -- > > > > John Larkin Highland Technology, Inc > > picosecond timing laser drivers and controllers > > > > jlarkin att highlandtechnology dott com > > http://www.highlandtechnology.com
On Tuesday, March 17, 2015 at 3:48:15 PM UTC-4, George Herold wrote:
> On Tuesday, March 17, 2015 at 1:08:23 PM UTC-4, bloggs.fred...@gmail.com wrote: > > On Monday, March 16, 2015 at 10:14:15 AM UTC-4, John Larkin wrote: > > > On Mon, 16 Mar 2015 17:39:17 +0800, McAvity <slider123@ebul.com> > > > wrote: > > > > > > >On 16-Mar-15 4:43 PM, Robert Baer wrote: > > > >> Patrick Chung wrote: > > > >>> Good feature of op-amp summing amplifier is that there is direct > > > >>> current path provided from every input to the output. For that reasons > > > >>> input voltage sources don't need to have current sink capability. > > > >>> Good feature of op-amp non inverting summing amplifier is that output > > > >>> voltage is proportional with the sum of the input signals, and with > > > >>> the same sign. Bad feature is that there is no direct current path > > > >>> from the inputs to the output, so input voltage sources must have > > > >>> sinking current capability. > > > >>> > > > >>> Read more: > > > >>> > > > >>> http://www.cirvirlab.com/index.php/tutorials/172-op-amp-summing-amplifier.html > > > >>> > > > >>> > > > >>> and also simulate: > > > >>> > > > >>> http://www.cirvirlab.com/simulation/op-amp-summing-amplifier-online.php > > > >>> http://www.cirvirlab.com/simulation/op-amp-non-inverting-summing-amplifier-online.php > > > >>> > > > >> Yawn.... > > > > > > > > > > > >Fair go, it might be yawn for you but it may be useful for others. > > > > > > > >Why not have a look and point out any errors if you spot them? > > > > > > Chung is a spammer, out to make money. He posts trivial, borderline > > > correct stuff. > > > > > > > > > > He's a Serbian trying to make some change on the side, give him a break! > > Huh? I don't mind him posting links to his web pages.. I guess what bothers me is that he doesn't respond to any of the input/ feedback that he gets from us. He's ignoring a chance to improve his web site.
If he relies on google translate, there is /definitely/ a language barrier. Serbians use both the Cyrillic and Latin alphabets so no problem there: http://en.wikipedia.org/wiki/Serbian_language
> > George H. > > > > > -- > > > > > > John Larkin Highland Technology, Inc > > > picosecond timing laser drivers and controllers > > > > > > jlarkin att highlandtechnology dott com > > > http://www.highlandtechnology.com