Groups > sci.electronics.design > #480933

About LEDs and LCDs

From	Jan Panteltje <pNaOnStPeAlMtje@yahoo.com>
Newsgroups	sci.electronics.design
Subject	About LEDs and LCDs
Date	2017-10-09 17:58 +0000
Organization	Datemas.de http://www.news.datemas.de
Message-ID	<orgdd0$4hf$1@news.datemas.de> (permalink)

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My lab power supply display slowly turned black during the last few month...:
 http://panteltje.com/pub/LCD_turning_black_IMG_6329.JPG

It is an old design and OK after all those years, but why does this process happen?
I once had an LCD watch and when sitting in the sun outside all of the sudden it turned black..
was very hot, bought a new one.
This thing has not been hot.

So, anyways had some other ones that did not fit, had a different driver, did not want to re-write the software, thing is way too good,
so ebay: found a Geeetech Yellow backlight LCD 1602 16x2 Characters display that claimed to have the same driver chip,
and same mechanical outline, start bid was 99 cents, so I did and got it, shipping 1 dollar.
Installed it yesterday.
Works perfectly, OR???
WOW such a bright backlight, blinding, switched it off again.
Checked the datasheet, maybe it needed a series resistor ??
Nope, 5V on the LED pins, resistor is on the module.
Still could not believe it, looked like a reading light, measured the current:
10 mA

Now you guys talk about LED aging, but it seems the newer ones are so good, those need attenuation.
Added 270 Ohm in series, now it is OK.
It is still bright in the evening, but no eye damage this way.

For new designs I only use OLED.

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Thread

About LEDs and LCDs Jan Panteltje <pNaOnStPeAlMtje@yahoo.com> - 2017-10-09 17:58 +0000
  Re: About LEDs and LCDs John Larkin <jjlarkin@highland_snip_technology.com> - 2017-10-09 11:20 -0700
    Re: About LEDs and LCDs Klaus Kragelund <klauskvik@hotmail.com> - 2017-10-09 11:42 -0700
      Re: About LEDs and LCDs Jan Panteltje <pNaonStpealmtje@yahoo.com> - 2017-10-09 19:24 +0000
        Re: About LEDs and LCDs klaus.kragelund@gmail.com - 2017-10-09 13:13 -0700
    Re: About LEDs and LCDs Jan Panteltje <pNaOnStPeAlMtje@yahoo.com> - 2017-10-09 19:08 +0000
  Re: About LEDs and LCDs bitrex <bitrex@de.lete.earthlink.net> - 2017-10-09 16:28 -0400
    Re: About LEDs and LCDs Jan Panteltje <pNaOnStPeAlMtje@yahoo.com> - 2017-10-10 08:16 +0000
    Re: About LEDs and LCDs Jan Panteltje <pNaOnStPeAlMtje@yahoo.com> - 2017-10-10 08:16 +0000
      Re: About LEDs and LCDs bitrex <bitrex@de.lete.earthlink.net> - 2017-10-10 08:06 -0400
        Re: About LEDs and LCDs Jan Panteltje <pNaonStpealmtje@yahoo.com> - 2017-10-10 15:08 +0000
          Re: About LEDs and LCDs Jan Panteltje <pNaonStpealmtje@yahoo.com> - 2017-10-10 15:13 +0000
            Re: About LEDs and LCDs Allan Herriman <allanherriman@hotmail.com> - 2017-10-10 23:21 +0000
          Re: About LEDs and LCDs Clifford Heath <no.spam@please.net> - 2017-10-11 10:58 +1100
            Re: About LEDs and LCDs Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-10-10 17:10 -0700
            Re: About LEDs and LCDs Jan Panteltje <pNaonStpealmtje@yahoo.com> - 2017-10-11 14:40 +0000
              Re: About LEDs and LCDs jack4747@gmail.com - 2017-10-11 07:45 -0700
                Re: About LEDs and LCDs Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-10-11 15:02 +0000
              Re: About LEDs and LCDs krw@notreal.com - 2017-10-11 21:03 -0400
                Re: About LEDs and LCDs Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-10-12 07:19 +0000
                Re: About LEDs and LCDs rickman <gnuarm@gmail.com> - 2017-10-12 13:07 -0400
                Re: About LEDs and LCDs Jan Panteltje <pNaOnStPeAlMtje@yahoo.com> - 2017-10-12 17:18 +0000
                Re: About LEDs and LCDs kevin93 <kevin@whitedigs.com> - 2017-10-12 19:30 -0700
                Re: About LEDs and LCDs krw@notreal.com - 2017-10-12 21:28 -0400
                Re: About LEDs and LCDs krw@notreal.com - 2017-10-12 20:55 -0400
              Re: About LEDs and LCDs Jasen Betts <jasen@xnet.co.nz> - 2017-10-12 04:22 +0000
          Re: About LEDs and LCDs Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-10-10 17:12 -0700
            Re: About LEDs and LCDs Jan Panteltje <pNa0nStpealmtje@yahoo.com> - 2017-10-11 14:41 +0000
  Re: About LEDs and LCDs Martin Brown <'''newspam'''@nezumi.demon.co.uk> - 2017-10-10 14:56 +0100
    Re: About LEDs and LCDs Jan Panteltje <pNaonStpealmtje@yahoo.com> - 2017-10-10 14:20 +0000

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