Re: inverting photo detector polarity on a microscope

Posted by Michael Giacomelli on
URL: http://confocal-microscopy-list.275.s1.nabble.com/inverting-photo-detector-polarity-on-a-microscope-tp7588654p7588660.html

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Thanks Craig.  It looks like I could modify the  THS3120EVM to operate at a
gain of -1 by swapping out some resistors.  The opamp itself is unity gain
stable.

Mike

On Thu, Sep 6, 2018 at 12:43 PM Craig Brideau <[hidden email]>
wrote:

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> *****
>
> You'd still need to apply a 2V offset then come down from that. By the time
> you splice in the bias offset you might as well have patched in an
> inverter.
> Craig
>
> On Wed, Sep 5, 2018 at 11:42 PM Mark Cannell <[hidden email]>
> wrote:
>
> > *****
> > To join, leave or search the confocal microscopy listserv, go to:
> > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> > Post images on http://www.imgur.com and include the link in your
> posting.
> > *****
> >
> > You could just record the data as is and invert the image afterwards?
> >
> > Mark B. Cannell. Ph.D. FRSNZ FISHR
> > Department of Physiology, Pharmacology & Neuroscience
> > School of Medical Sciences
> > University Walk
> > Bristol BS8 1TD
> >
> > [hidden email]
> >
> >
> >
> > On 6/09/18, 2:23 AM, "Confocal Microscopy List on behalf of Edward
> > Allgeyer" <[hidden email] on behalf of [hidden email]
> >
> > wrote:
> >
> >     *****
> >     To join, leave or search the confocal microscopy listserv, go to:
> >     http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> >     Post images on http://www.imgur.com and include the link in your
> > posting.
> >     *****
> >
> >     Hi Mike,
> >
> >     I have no commercial interest in either of the things I'm going to
> > mention
> >     but they maybe of interest to you.
> >
> >     First, there is a California based company, Pulse Research Lab, that
> > sells
> >     a selection of high speed off the shelf comparators/sine wave
> > converters
> >     that I've had success with for similar purposes. Their comparators
> are
> >     fairly forgiving with what you connect as the input and you have a
> > number
> >     of options for the corresponding output. You can browse their
> selection
> >     here:
> >
> >
> >
> https://www.pulseresearchlab.com/collections/comparators-sinewave-converters-1
> >
> >     I'll also mention that on their comparators they have preset
> > thresholds but
> >     you can also set an arbitrary threshold by applying a DC voltage to
> the
> >     complementary input if you want to.
> >
> >     Second, Picoquant also sells a few inverters and adaptors that might
> > work
> >     for you. Specifically the SI100 is a passive inline pulse inverter
> and
> >     might work for your application. You can browse their adapters,
> > splitters
> >     and cables here:
> >
> >
> >
> https://www.picoquant.com/products/category/accessories/adapters-splitters-cables-various-accessories-for-photon-counting-setups
> >
> >     Hopefully this helps. Again, no commercial interest in either of
> these
> >     companies. Just thought I'd mention them as possible options.
> >
> >     Best,
> >     Ed
> >
> >     On Wed, Sep 5, 2018 at 12:58 PM Michael Giacomelli <[hidden email]>
> > wrote:
> >
> >     > *****
> >     > To join, leave or search the confocal microscopy listserv, go to:
> >     > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> >     > Post images on http://www.imgur.com and include the link in your
> > posting.
> >     > *****
> >     >
> >     > Hi,
> >     >
> >     > I would like to test out a new detector module in a commerical
> > Olympus
> >     > confocal body.  Unfortunately, the detector uses an inverting
> > amplifier
> >     > (0->-1 V), while the Olympus assumes a non-inverting transimpedance
> >     > amplifier (0->+1 V).  I've spoken with them and there is no way to
> > change
> >     > the A/D configuration on this specific model, and so I cannot use
> the
> >     > detector as is.
> >     >
> >     > Is there a commerical solution available for adapting something
> like
> > this?
> >     > I would like to avoid having to design and breadboard an inverting
> > buffer
> >     > amplifier if I can avoid it.
> >     >
> >     > Thanks,
> >     > Mike
> >     >
> >
> >
> >
>