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Re: [Electronics_101] Why IC's are black in colour?

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  • Leon
    ... From: abhi_ah28 To: Sent: Sunday, June 01, 2008 5:55 PM Subject: [Electronics_101] Why IC s are
    Message 1 of 8 , Jun 1 2:39 PM
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      ----- Original Message -----
      From: "abhi_ah28" <abhi_ah28@...>
      To: <Electronics_101@yahoogroups.com>
      Sent: Sunday, June 01, 2008 5:55 PM
      Subject: [Electronics_101] Why IC's are black in colour?


      >I searched the whole web and didnt find an acceptable solution.
      > Can anyone tell me why is it so!....

      I had some red TTL chips many years ago. They were made by Mitsubishi, IIRC.

      Leon
      --
      Leon Heller
      Amateur radio call-sign G1HSM
      Yaesu FT-817ND transceiver
      Suzuki SV1000S motorcycle
      leon355@...
      http://www.geocities.com/leon_heller
    • Shawn Upton
      Great question; beats me. I do know that opto-isolators tend to be white, so as to help with efficency; but that s about the only other color I have seen. If
      Message 2 of 8 , Jun 1 2:57 PM
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        Great question; beats me. I do know that opto-isolators tend to be white, so as to help with efficency; but that's about the only other color I have seen. If I had to guess, it comes down to a) cheap epoxy used to encapsulate happens to be cheapest in black, b) they are "doping" said epoxy with something black in color, in order to get the coefficent of expansion the same as it is for the silicon, and/or c) it helps ensure that no stray photo will make it through the package, no matter how strong the light is (pretty unlikely but I just happened to think of it). I'll try digging into this week and see if I can find an answer.

        Shawn Upton, KB1CKT



        ----- Original Message ----
        From: abhi_ah28 <abhi_ah28@...>
        To: Electronics_101@yahoogroups.com
        Sent: Sunday, June 1, 2008 12:55:22 PM
        Subject: [Electronics_101] Why IC's are black in colour?


        I searched the whole web and didnt find an acceptable solution.
        Can anyone tell me why is it so!....

        _




        [Non-text portions of this message have been removed]
      • Roy J. Tellason
        ... Oh? That s the first I ve heard of that as being a reason for that color case. Though I have some that are in other colors as well. ... I have some that
        Message 3 of 8 , Jun 1 5:00 PM
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          On Sunday 01 June 2008 17:57, Shawn Upton wrote:
          > Great question; beats me. I do know that opto-isolators tend to be white,
          > so as to help with efficency;

          Oh? That's the first I've heard of that as being a reason for that color
          case. Though I have some that are in other colors as well.

          > but that's about the only other color I have seen.

          I have some that are gray, and some that are a greenish color, I'm not sure
          who makes those.

          > If I had to guess, it comes down to a) cheap epoxy used to encapsulate
          > happens to be cheapest in black,

          I haven't noticed any particular color to most epoxies I've used. There are
          times though when there's filler used. And for that black is cheapest,
          because (as I found out with automotive-type batteries), recycling a whole
          mess of different kind of plastic materials gives you black. :-)

          > b) they are "doping" said epoxy with something black in color, in order to
          > get the coefficent of expansion the same as it is for the silicon, and/or

          The coefficient of expansion needs to match the lead frame, not the silicon.

          > c) it helps ensure that no stray photo will make it through the package, no
          > matter how strong the light is (pretty unlikely but I just happened to think
          > of it).

          Opaque is probably good, yeah.

          > I'll try digging into this week and see if I can find an answer.

          Somebody else mentioned red, I've never seen any red chips. Black, gray
          (both gray plastic and ceramic), white ceramic, though usually with a metal
          cap over the actual chip, that greenish color I mentioned above, and the
          off-white color of many optos (though some of those are in other colors as
          well).

          --
          Member of the toughest, meanest, deadliest, most unrelenting -- and
          ablest -- form of life in this section of space,  a critter that can
          be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
          -
          Information is more dangerous than cannon to a society ruled by lies. --James
          M Dakin
        • logicresearch
          I have seen (and think I still have) a white one. To think of it, I think it is an optoisolator. Will have to dig it out. daryl. ... be white, ... color ...
          Message 4 of 8 , Jun 1 5:42 PM
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            I have seen (and think I still have) a white one.
            To think of it, I think it is an optoisolator.
            Will have to dig it out.

            daryl.

            --- In Electronics_101@yahoogroups.com, "Roy J. Tellason"
            <rtellason@...> wrote:
            >
            > On Sunday 01 June 2008 17:57, Shawn Upton wrote:
            > > Great question; beats me. I do know that opto-isolators tend to
            be white,
            > > so as to help with efficency;
            >
            > Oh? That's the first I've heard of that as being a reason for that
            color
            > case. Though I have some that are in other colors as well.
            >
            > > but that's about the only other color I have seen.
            >
            > I have some that are gray, and some that are a greenish color, I'm
            not sure
            > who makes those.
            >
            > > If I had to guess, it comes down to a) cheap epoxy used to encapsulate
            > > happens to be cheapest in black,
            >
            > I haven't noticed any particular color to most epoxies I've used.
            There are
            > times though when there's filler used. And for that black is
            cheapest,
            > because (as I found out with automotive-type batteries), recycling
            a whole
            > mess of different kind of plastic materials gives you black. :-)
            >
            > > b) they are "doping" said epoxy with something black in color, in
            order to
            > > get the coefficent of expansion the same as it is for the silicon,
            and/or
            >
            > The coefficient of expansion needs to match the lead frame, not the
            silicon.
            >
            > > c) it helps ensure that no stray photo will make it through the
            package, no
            > > matter how strong the light is (pretty unlikely but I just
            happened to think
            > > of it).
            >
            > Opaque is probably good, yeah.
            >
            > > I'll try digging into this week and see if I can find an answer.
            >
            > Somebody else mentioned red, I've never seen any red chips. Black,
            gray
            > (both gray plastic and ceramic), white ceramic, though usually
            with a metal
            > cap over the actual chip, that greenish color I mentioned above,
            and the
            > off-white color of many optos (though some of those are in other
            colors as
            > well).
            >
            > --
            > Member of the toughest, meanest, deadliest, most unrelenting -- and
            > ablest -- form of life in this section of space, a critter that can
            > be killed but can't be tamed. --Robert A. Heinlein, "The Puppet
            Masters"
            > -
            > Information is more dangerous than cannon to a society ruled by
            lies. --James
            > M Dakin
            >
          • logicresearch
            Yep, look at that - a white 4N33. Daryl. ... encapsulate
            Message 5 of 8 , Jun 1 5:44 PM
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              Yep, look at that - a white 4N33.

              Daryl.


              --- In Electronics_101@yahoogroups.com, "logicresearch"
              <logicresearch@...> wrote:
              >
              > I have seen (and think I still have) a white one.
              > To think of it, I think it is an optoisolator.
              > Will have to dig it out.
              >
              > daryl.
              >
              > --- In Electronics_101@yahoogroups.com, "Roy J. Tellason"
              > <rtellason@> wrote:
              > >
              > > On Sunday 01 June 2008 17:57, Shawn Upton wrote:
              > > > Great question; beats me. I do know that opto-isolators tend to
              > be white,
              > > > so as to help with efficency;
              > >
              > > Oh? That's the first I've heard of that as being a reason for that
              > color
              > > case. Though I have some that are in other colors as well.
              > >
              > > > but that's about the only other color I have seen.
              > >
              > > I have some that are gray, and some that are a greenish color, I'm
              > not sure
              > > who makes those.
              > >
              > > > If I had to guess, it comes down to a) cheap epoxy used to
              encapsulate
              > > > happens to be cheapest in black,
              > >
              > > I haven't noticed any particular color to most epoxies I've used.
              > There are
              > > times though when there's filler used. And for that black is
              > cheapest,
              > > because (as I found out with automotive-type batteries), recycling
              > a whole
              > > mess of different kind of plastic materials gives you black. :-)
              > >
              > > > b) they are "doping" said epoxy with something black in color, in
              > order to
              > > > get the coefficent of expansion the same as it is for the silicon,
              > and/or
              > >
              > > The coefficient of expansion needs to match the lead frame, not the
              > silicon.
              > >
              > > > c) it helps ensure that no stray photo will make it through the
              > package, no
              > > > matter how strong the light is (pretty unlikely but I just
              > happened to think
              > > > of it).
              > >
              > > Opaque is probably good, yeah.
              > >
              > > > I'll try digging into this week and see if I can find an answer.
              > >
              > > Somebody else mentioned red, I've never seen any red chips. Black,
              > gray
              > > (both gray plastic and ceramic), white ceramic, though usually
              > with a metal
              > > cap over the actual chip, that greenish color I mentioned above,
              > and the
              > > off-white color of many optos (though some of those are in other
              > colors as
              > > well).
              > >
              > > --
              > > Member of the toughest, meanest, deadliest, most unrelenting -- and
              > > ablest -- form of life in this section of space, a critter that can
              > > be killed but can't be tamed. --Robert A. Heinlein, "The Puppet
              > Masters"
              > > -
              > > Information is more dangerous than cannon to a society ruled by
              > lies. --James
              > > M Dakin
              > >
              >
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