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Sensitivity AND Parts Galore! — Parallax Forums

Sensitivity AND Parts Galore!

ArchiverArchiver Posts: 46,084
edited 2001-12-29 19:42 in General Discussion
Photoresistor and Phototransistor sensitivity. I have one of the small 5 piece
photoresistor packs from Radio Shack. The only thing is, they are not that
sensitive. The largest one is the best, but not superb. So where can I get the
MOST sensitive photocell? I can only assume that phototransistors must be the
same way, so where's a good place to get those? Also, a more general question, I
would like all of you to post up as many Electronic Parts dealers as you can.
That would help me and I'm sure help others. Thanks to all!
AF


[noparse][[/noparse]Non-text portions of this message have been removed]

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2001-12-29 03:13
    I have just created a database on yahoo groups here for electronic part
    dealers:
    http://groups.yahoo.com/group/basicstamps/database?method=reportRows&tbl=4

    <http://groups.yahoo.com/group/basicstamps/database?method=reportRows&tbl=4>

    http://groups.yahoo.com/group/basicstamps
    Tad Heckaman

    Original Message
    From: "Astro Fizzix" <astro_fizzix@y...>
    To: "Post BS Message" <basicstamps@yahoogroups.com>
    Sent: Friday, December 28, 2001 9:48 PM
    Subject: [noparse][[/noparse]basicstamps] Sensitivity AND Parts Galore!


    > Photoresistor and Phototransistor sensitivity. I have one of the small 5
    piece photoresistor packs from Radio Shack. The only thing is, they are not
    that sensitive. The largest one is the best, but not superb. So where can I
    get the MOST sensitive photocell? I can only assume that phototransistors
    must be the same way, so where's a good place to get those? Also, a more
    general question, I would like all of you to post up as many Electronic
    Parts dealers as you can. That would help me and I'm sure help others.
    Thanks to all!
    > AF
    >
    >
    > [noparse][[/noparse]Non-text portions of this message have been removed]
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and
    Body of the message will be ignored.
    >
    >
    > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
    >
  • ArchiverArchiver Posts: 46,084
    edited 2001-12-29 03:33
    Forgive my ignorance, but Yahoo wouldn't let me in. I have been on the
    Stamp list for well over a year, but trying their help system didn't work.
    Any suggestions?

    Thanks in advance,
    Ray McArthur

    Original Message
    From: tad heckaman.com <tad@h...>
    To: <basicstamps@yahoogroups.com>
    Sent: Friday, December 28, 2001 10:13 PM
    Subject: Re: [noparse][[/noparse]basicstamps] Sensitivity AND Parts Galore!


    > I have just created a database on yahoo groups here for electronic part
    > dealers:
    > http://groups.yahoo.com/group/basicstamps/database?method=reportRows&tbl=4
    >
    >
    <http://groups.yahoo.com/group/basicstamps/database?method=reportRows&tbl=4>
    >
    > http://groups.yahoo.com/group/basicstamps
    > Tad Heckaman
  • ArchiverArchiver Posts: 46,084
    edited 2001-12-29 03:51
    There are some optointerupter pairs that have an amp or one-shot on the
    detector that makes them very clean at high count rates. I had some salvaged
    from a piece of equipment that would read a 60-slot wheel turning at about
    10,000 rpm (with an OOPic though) I would assume you can buy just a detector
    with the same feature.

    Original Message

    > Photoresistor and Phototransistor sensitivity. I have one of the small 5
    piece photoresistor packs from Radio Shack. The only thing is, they are not
    that sensitive. The largest one is the best, but not superb. So where can I
    get the MOST sensitive photocell? I can only assume that phototransistors
    must be the same way, so where's a good place to get those? Also, a more
    general question, I would like all of you to post up as many Electronic
    Parts dealers as you can. That would help me and I'm sure help others.
    Thanks to all!
  • ArchiverArchiver Posts: 46,084
    edited 2001-12-29 03:55
    Hmmm seems like the moderator of the list wont let guests in. you can make a
    brand new user and then try again. I guess you joined by useing the 'join
    now' link on parallax.com? all it does is join you without making a user
    account. if you made a usr account then this is beyond me [noparse]:)[/noparse]

    tad
    Original Message
    From: "Ray McArthur" <rjmca@u...>
    To: <basicstamps@yahoogroups.com>
    Sent: Friday, December 28, 2001 10:33 PM
    Subject: Re: [noparse][[/noparse]basicstamps] Sensitivity AND Parts Galore!


    > Forgive my ignorance, but Yahoo wouldn't let me in. I have been on the
    > Stamp list for well over a year, but trying their help system didn't work.
    > Any suggestions?
    >
    > Thanks in advance,
    > Ray McArthur
    >
    >
    Original Message
    > From: tad heckaman.com <tad@h...>
    > To: <basicstamps@yahoogroups.com>
    > Sent: Friday, December 28, 2001 10:13 PM
    > Subject: Re: [noparse][[/noparse]basicstamps] Sensitivity AND Parts Galore!
    >
    >
    > > I have just created a database on yahoo groups here for electronic part
    > > dealers:
    > >
    http://groups.yahoo.com/group/basicstamps/database?method=reportRows&tbl=4
    > >
    > >
    >
    <http://groups.yahoo.com/group/basicstamps/database?method=reportRows&tbl=4>
    > >
    > > http://groups.yahoo.com/group/basicstamps
    > > Tad Heckaman
    >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and
    Body of the message will be ignored.
    >
    >
    > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
    >
  • ArchiverArchiver Posts: 46,084
    edited 2001-12-29 04:42
    >must be the same way, so where's a good place to get those? Also, a more
    >general question, I would like all of you to post up as many Electronic
    >Parts dealers as you can. That would help me and I'm sure help others.
    >Thanks to all!

    Most of my parts come from these suppliers:

    https://www.jameco.com
    http://www.digikey.com/
    http://www.mouser.com/

    They all ship Priority Mail. Anything else to Hawaii is too expensive.

    I only use http://www.alliedelec.com/ as a last resort because they do not
    ship Priority Mail.

    Use this page to look for chips http://www.findchips.com/

    This phototransistor works well

    http://www.jameco.com/cgi-bin/ncommerce3/ExecMacro/Jameco/searchResult.d2w/r
    eport?sort=&search=bpw77

    This photodiode is more sensitive than the transistor

    http://www.mouser.com/products/detail.cfm?mpart=78-BPW46L&CustRef=&source=se
    arch&CFID=11243399&CFTOKEN=66568210

    Jay



    [noparse][[/noparse]Non-text portions of this message have been removed]
  • ArchiverArchiver Posts: 46,084
    edited 2001-12-29 15:46
    >Photoresistor and Phototransistor sensitivity. I have one of the
    >small 5 piece photoresistor packs from Radio Shack. The only thing
    >is, they are not that sensitive. The largest one is the best, but
    >not superb. So where can I get the MOST sensitive photocell? I can
    >only assume that phototransistors must be the same way, so where's a
    >good place to get those? Also, a more general question, I would like
    >all of you to post up as many Electronic Parts dealers as you can.
    >That would help me and I'm sure help others. Thanks to all!
    >AF
    >


    Multiplier phototubes can detect starlight. Exoect a major
    learning curve if you want to use them. They also are large,
    expensive and very hardware-intensive. They require
    high-voltage power supplies and magnetic shielding.
    But if you want to detect single photons, they can do it.

    Reg Neale
  • ArchiverArchiver Posts: 46,084
    edited 2001-12-29 15:57
    Used to work on tools that used this in conjunction with a sodium iodide
    crystal to detect gamma radiation. Pretty nifty setup -- what we built fit
    in a 2" metal housing and ran off a 100 volt DC power supply. The downside
    is the tube and crystal are very fragile and you must protect them PM tube
    from stray light while its powered up.

    Original Message

    > >Photoresistor and Phototransistor sensitivity. I have one of the
    > >small 5 piece photoresistor packs from Radio Shack. The only thing
    > >is, they are not that sensitive. The largest one is the best, but
    > >not superb. So where can I get the MOST sensitive photocell? I can
    > >only assume that phototransistors must be the same way, so where's a
    > >good place to get those? Also, a more general question, I would like
    > >all of you to post up as many Electronic Parts dealers as you can.
    > >That would help me and I'm sure help others. Thanks to all!
    > >AF
    > >
    >
    >
    > Multiplier phototubes can detect starlight. Exoect a major
    > learning curve if you want to use them. They also are large,
    > expensive and very hardware-intensive. They require
    > high-voltage power supplies and magnetic shielding.
    > But if you want to detect single photons, they can do it.
  • ArchiverArchiver Posts: 46,084
    edited 2001-12-29 19:42
    Probably the most sensitive item is the 931a photomultiplier tube. It needs
    a psu of 1000 volts, but at low current, so a simple multiplier chain from a
    old flash tube module will do. the PDF location is below:

    You can drive a vn66af power mosfet straight from the output via a say 1pf
    capacitor into a voltage divider on the fet gate for bias. Makes a nice
    click on a loudspeaker. You can use a larger capacitor for more power but
    lower bandwith.

    The only disadvantage is that it saturates easily with too much light.

    I've used it in the past when experimenting with scintillation chambers.

    http://www.burle.com/cgi-bin/byteserver.pl/pdf/931a.pdf

    Regards,

    Tony Wells
    Original Message
    From: "Rodent" <daweasel@s...>
    To: <basicstamps@yahoogroups.com>
    Sent: Saturday, December 29, 2001 3:57 PM
    Subject: Re: [noparse][[/noparse]basicstamps] Sensitivity AND Parts Galore!


    > Used to work on tools that used this in conjunction with a sodium iodide
    > crystal to detect gamma radiation. Pretty nifty setup -- what we built fit
    > in a 2" metal housing and ran off a 100 volt DC power supply. The downside
    > is the tube and crystal are very fragile and you must protect them PM tube
    > from stray light while its powered up.
    >
    >
    Original Message
    >
    > > >Photoresistor and Phototransistor sensitivity. I have one of the
    > > >small 5 piece photoresistor packs from Radio Shack. The only thing
    > > >is, they are not that sensitive. The largest one is the best, but
    > > >not superb. So where can I get the MOST sensitive photocell? I can
    > > >only assume that phototransistors must be the same way, so where's a
    > > >good place to get those? Also, a more general question, I would like
    > > >all of you to post up as many Electronic Parts dealers as you can.
    > > >That would help me and I'm sure help others. Thanks to all!
    > > >AF
    > > >
    > >
    > >
    > > Multiplier phototubes can detect starlight. Exoect a major
    > > learning curve if you want to use them. They also are large,
    > > expensive and very hardware-intensive. They require
    > > high-voltage power supplies and magnetic shielding.
    > > But if you want to detect single photons, they can do it.
    >
    >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and
    Body of the message will be ignored.
    >
    >
    > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
    >
    >
    >
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