Posted by
Zdenek Svindrych-2 on
URL: http://confocal-microscopy-list.275.s1.nabble.com/inverting-photo-detector-polarity-on-a-microscope-tp7588654p7588662.html
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Hi Mike,
great choice! The opamp itself (and the module as well) is geared towards
non-inverting configuration, but it will work OK for you.
Obviously you don't want the inverting input shorted to ground, but proper
50 Ohm input impedance (as long as the other components - the detector and
the Olympus ADC - are 50 Ohm). Looks like easy fix.
Good luck!
zdenek
---------- Původní e-mail ----------
Od: Michael Giacomelli <
[hidden email]>
Komu:
[hidden email]
Datum: 6. 9. 2018 13:13:49
Předmět: Re: inverting photo detector polarity on a microscope
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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:
> *****
> To join, leave or search the confocal microscopy listserv, go to:
>
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy> Post images on
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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
> > >
> >
> >
> >
>
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