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1957 LED

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  1957 LED hancock4@bbs.cpcn.com - 2015-12-10 11:03 -0800
    Re: 1957 LED Al Kossow <aek@bitsavers.org> - 2015-12-10 11:06 -0800
      Re: 1957 LED Michael Black <et472@ncf.ca> - 2015-12-10 14:44 -0500
        Re: 1957 LED hancock4@bbs.cpcn.com - 2015-12-11 07:41 -0800
          Re: 1957 LED Ahem A Rivet's Shot <steveo@eircom.net> - 2015-12-11 16:37 +0000
          Re: 1957 LED Michael Black <et472@ncf.ca> - 2015-12-11 14:42 -0500
      Re: 1957 LED philo <philo@privacy.net> - 2015-12-10 13:56 -0600
        Re: 1957 LED Michael Black <et472@ncf.ca> - 2015-12-10 22:59 -0500
          Re: 1957 LED "Osmium" <r124c4u102@comcast.net> - 2015-12-11 08:20 -0600
            Re: 1957 LED Michael Black <et472@ncf.ca> - 2015-12-11 14:33 -0500
        Re: 1957 LED Quadibloc <jsavard@ecn.ab.ca> - 2015-12-13 07:58 -0800
          Re: 1957 LED Michael Black <et472@ncf.ca> - 2015-12-13 13:00 -0500
        Re: 1957 LED Lon <lon.stowell@comcast.net> - 2015-12-13 12:48 -0700
          Re: 1957 LED Stan Barr <plan.b@bluesomatic.org> - 2015-12-14 09:07 +0000
            Re: 1957 LED Michael Black <et472@ncf.ca> - 2015-12-14 11:47 -0500
            Re: 1957 LED rpw3@rpw3.org (Rob Warnock) - 2015-12-16 14:55 +0000
              Re: 1957 LED Stan Barr <plan.b@bluesomatic.org> - 2015-12-16 16:32 +0000
                Re: 1957 LED Michael Black <et472@ncf.ca> - 2015-12-16 14:17 -0500
                Re: 1957 LED "Charles Richmond" <numerist@aquaporin4.com> - 2015-12-16 18:15 -0600
                  Re: 1957 LED Stan Barr <plan.b@bluesomatic.org> - 2015-12-17 07:58 +0000
                  Re: 1957 LED Andrew Swallow <am.swallow@btinternet.com> - 2015-12-17 13:21 +0000
          Re: 1957 LED Ingo Paschke <ipaschke@lpclabs.de> - 2015-12-14 11:11 +0100
      Re: 1957 LED Stephen Wolstenholme <steve@easynn.com> - 2015-12-11 10:58 +0000
        Re: 1957 LED Lon <lon.stowell@comcast.net> - 2015-12-13 12:50 -0700
          Re: 1957 LED Stephen Wolstenholme <steve@easynn.com> - 2015-12-14 12:57 +0000
            Re: 1957 LED "gareth" <no.spam@thank.you.invalid> - 2015-12-14 14:07 +0000
              Re: 1957 LED Stephen Wolstenholme <steve@easynn.com> - 2015-12-14 14:33 +0000
      Re: 1957 LED hancock4@bbs.cpcn.com - 2015-12-11 07:31 -0800
        Re: 1957 LED Quadibloc <jsavard@ecn.ab.ca> - 2015-12-13 07:42 -0800
          Re: 1957 LED Ahem A Rivet's Shot <steveo@eircom.net> - 2015-12-14 09:39 +0000
          Re: 1957 LED Jon Elson <jmelson@wustl.edu> - 2015-12-14 17:07 -0600
            Re: 1957 LED Alfred Falk <falk@arc.ab.ca> - 2015-12-15 18:53 +0000
              Re: 1957 LED Michael Black <et472@ncf.ca> - 2015-12-15 15:05 -0500
                Re: 1957 LED hancock4@bbs.cpcn.com - 2015-12-16 07:32 -0800
                  Re: 1957 LED Alfred Falk <falk@arc.ab.ca> - 2015-12-16 17:23 +0000
                  Re: 1957 LED Michael Black <et472@ncf.ca> - 2015-12-16 14:23 -0500
                    Re: 1957 LED Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2015-12-16 20:13 +0000
                      Re: 1957 LED hancock4@bbs.cpcn.com - 2015-12-16 13:15 -0800
                      Re: 1957 LED Michael Black <et472@ncf.ca> - 2015-12-17 14:53 -0500
                        Re: 1957 LED "Charles Richmond" <numerist@aquaporin4.com> - 2015-12-17 14:17 -0600
                          Re: 1957 LED Michael Black <et472@ncf.ca> - 2015-12-18 19:43 -0500
                            Re: 1957 LED "Charles Richmond" <numerist@aquaporin4.com> - 2015-12-20 20:02 -0600
                            Re: 1957 LED hancock4@bbs.cpcn.com - 2015-12-21 10:31 -0800
                              Re: 1957 LED Michael Black <et472@ncf.ca> - 2015-12-21 14:53 -0500
                                Re: 1957 LED mausg@mail.com - 2015-12-21 20:27 +0000
                    Re: 1957 LED Uncle Steve <stevet810@gmail.com> - 2015-12-17 18:48 -0500
            Re: 1957 LED davidmylastname@acm.org (David Griffith) - 2015-12-16 02:43 +0000
            Re: 1957 LED Mike Spencer <mds@bogus.nodomain.nowhere> - 2015-12-16 17:44 -0400
    Re: 1957 LED scott@slp53.sl.home (Scott Lurndal) - 2015-12-10 19:13 +0000
      Re: 1957 LED "gareth" <no.spam@thank.you.invalid> - 2015-12-10 20:17 +0000
        Re: 1957 LED Lawrence Statton <lawrence@sengiuo.mx> - 2015-12-10 17:10 -0600
        Re: 1957 LED Michael Black <et472@ncf.ca> - 2015-12-10 23:00 -0500
          Re: 1957 LED isw <isw@witzend.com> - 2015-12-10 21:21 -0800
            Re: 1957 LED Stan Barr <plan.b@bluesomatic.org> - 2015-12-11 08:01 +0000
              Re: 1957 LED Michael Black <et472@ncf.ca> - 2015-12-11 14:30 -0500
              Re: 1957 LED "Charles Richmond" <numerist@aquaporin4.com> - 2015-12-11 15:36 -0600
                Re: 1957 LED Stan Barr <plan.b@bluesomatic.org> - 2015-12-12 07:55 +0000
                  Re: 1957 LED mausg@mail.com - 2015-12-12 11:20 +0000
                    Re: 1957 LED Stan Barr <plan.b@bluesomatic.org> - 2015-12-12 15:39 +0000
                    Re: 1957 LED Michael Black <et472@ncf.ca> - 2015-12-12 10:50 -0500
                      Re: 1957 LED Stan Barr <plan.b@bluesomatic.org> - 2015-12-13 08:00 +0000
                        Re: 1957 LED "gareth" <no.spam@thank.you.invalid> - 2015-12-13 11:10 +0000
                Re: 1957 LED Lon <lon.stowell@comcast.net> - 2015-12-13 12:51 -0700
          Re: 1957 LED "gareth" <no.spam@thank.you.invalid> - 2015-12-11 10:59 +0000
            Re: 1957 LED Ahem A Rivet's Shot <steveo@eircom.net> - 2015-12-11 15:46 +0000
              Re: 1957 LED "gareth" <no.spam@thank.you.invalid> - 2015-12-11 17:37 +0000
                Re: 1957 LED Ahem A Rivet's Shot <steveo@eircom.net> - 2015-12-11 18:34 +0000
                  Re: 1957 LED Michael Black <et472@ncf.ca> - 2015-12-11 14:49 -0500
                  Re: 1957 LED "Charles Richmond" <numerist@aquaporin4.com> - 2015-12-11 15:39 -0600
                    Re: 1957 LED Bob Eager <news0005@eager.cx> - 2015-12-11 22:46 +0000
                    Re: 1957 LED Michael Black <et472@ncf.ca> - 2015-12-11 19:07 -0500
                      Re: 1957 LED Bob Eager <news0005@eager.cx> - 2015-12-12 01:04 +0000
                      Re: 1957 LED Ahem A Rivet's Shot <steveo@eircom.net> - 2015-12-12 08:54 +0000
          Re: 1957 LED hancock4@bbs.cpcn.com - 2015-12-11 11:52 -0800
            Re: 1957 LED "Charles Richmond" <numerist@aquaporin4.com> - 2015-12-11 15:46 -0600
              Re: 1957 LED Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2015-12-11 22:56 +0000
          Re: 1957 LED "Charles Richmond" <numerist@aquaporin4.com> - 2015-12-11 15:35 -0600
          Re: 1957 LED Quadibloc <jsavard@ecn.ab.ca> - 2015-12-13 07:51 -0800
    Re: 1957 LED Lawrence Statton <lawrence@senguio.mx> - 2015-12-10 17:09 -0600

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#155339

On Thu, 17 Dec 2015, Charles Richmond wrote:

> "Michael Black" <et472@ncf.ca> wrote in message 
> news:alpine.LNX.2.02.1512171448410.9567@darkstar.example.org...
>> On Wed, 16 Dec 2015, Charlie Gibbs wrote:
>>
>>       [snip...]                      [snip...] [snip...]
>>> I too am tired of this never-ending stream of exotic batteries
>>> which are only compatible with the camera du jour - but at least
>>> they seem to be a better match electrically.
>>> 
>> I bought a pair of FRS walkie talkies at a garage sale, no charger, for 
>> five dollars.  They were actually in with the toys.  They actually come 
>> with a pack of rechargeable batteries, but so organized that regular AAA 
>> batteries can be used too.  That seems like maybe the best solution.
>> 
>> I've yet to try them as walkie-talkies, I discovered they have the ability 
>> to receive the weather stations at 162MHz, and these are realy good at 
>> that.  Beats the Weatherradio I had forty years ago from Radio Shack, beats 
>> the windup Eton "emergency" radio I found a few years ago.
>> 
>
> Michael, you pick up so much junk you remind me of another Black... Fred 
> Sanford.  ;-)  You just need an old beat-up pick up truck and you're in 
> business!!!
>
It's better to let someone else pay the full price for such things.  If I 
didn't find it cheap or free, I wouldn't be buying it new.

   Michael

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#155392

"Michael Black" <et472@ncf.ca> wrote in message 
news:alpine.LNX.2.02.1512181943280.11445@darkstar.example.org...
>>
>>             [snip...]                  [snip...] 
>> [snip...]
>>
>> Michael, you pick up so much junk you remind me of another Black... Fred 
>> Sanford.  ;-)  You just need an old beat-up pick up truck and you're in 
>> business!!!
>>
> It's better to let someone else pay the full price for such things.  If I 
> didn't find it cheap or free, I wouldn't be buying it new.
>

Still, some of your "finds" make for interesting stories...

-- 

numerist at aquaporin4 do tomc

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#155403

On Friday, December 18, 2015 at 7:40:30 PM UTC-5, Michael Black wrote:


> It's better to let someone else pay the full price for such things.  If I 
> didn't find it cheap or free, I wouldn't be buying it new.

I'm envious that you can find so much old electronic gear and
salvage it into something useful.  I'd figure that anything
remotely modern with solid state boards wouldn't be repairable.

Of course, the Computer Museum managed to find an old 1401 and
repair it so that it runs.

(Too bad you're in Canada.  I'd bring you my Aiwa stereo with the
broken tape decks for repair.)


I bought an SCM electronic typewriter at a yard sale.  The machine
had the manual and was in good working order, except that it
needed a ribbon.  Turned out the ribbon was only available
through a specialty house, $35 + s&h.  Not worth it to me,
threw the machine out.  (Plus, in reading the manual, I 
discovered the machine's "electronic" functionality was very
limited, it basically could backspace over an error in the line
and center text.  Not much more than a plain typewriter, for
which ribbons are easy to get.)

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#155405

On Mon, 21 Dec 2015, hancock4@bbs.cpcn.com wrote:

> On Friday, December 18, 2015 at 7:40:30 PM UTC-5, Michael Black wrote:
>
>
>> It's better to let someone else pay the full price for such things.  If I
>> didn't find it cheap or free, I wouldn't be buying it new.
>
> I'm envious that you can find so much old electronic gear and
> salvage it into something useful.  I'd figure that anything
> remotely modern with solid state boards wouldn't be repairable.
>
Pretty much all of it is still working.

It's people who've bought the next newest thing, so they no longer like 
that GPS that doesn't do maps.  That five dollar GPS receiver is amazing, 
how do they get all that microwave stuff in that small package?  If 
actually went into the wilderness, it would be extremely useful.  In the 
city, less so, since I don't generally have coordinates for where I'm 
going.  The ten dollar GPS did do maps, that's harder to understand why 
someone gave that up to the Rotary Club where I bought it.  It's intended 
for car use, so the battery inside doesn't last very long.


> Of course, the Computer Museum managed to find an old 1401 and
> repair it so that it runs.
>
> (Too bad you're in Canada.  I'd bring you my Aiwa stereo with the
> broken tape decks for repair.)
>
>
> I bought an SCM electronic typewriter at a yard sale.  The machine
> had the manual and was in good working order, except that it
> needed a ribbon.  Turned out the ribbon was only available
> through a specialty house, $35 + s&h.  Not worth it to me,
> threw the machine out.  (Plus, in reading the manual, I
> discovered the machine's "electronic" functionality was very
> limited, it basically could backspace over an error in the line
> and center text.  Not much more than a plain typewriter, for
> which ribbons are easy to get.)
>
>
I suppose that was scrapped because it was a typewriter, but maybe
they did decide it was time to move up once the ribbon got so expensive.

It's easy to see DVD players waiting for the garbage, but mostly they have 
no remote.  It makes me wonder if someone lost the remote, and then scraps 
the DVD player.  Some of it has to be moving up to blu-ray, but maybe not 
all.  On the other hand, it's not uncommon to see the remotes separately, 
as if they've been found long after the equipment was discarded.  I even 
once found a remote for the VCR I bought at a garage sale, so I had a 
spare.

   Michael

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#155413

On 2015-12-21, Michael Black <et472@ncf.ca> wrote:
> On Mon, 21 Dec 2015, hancock4@bbs.cpcn.com wrote:
>
>> On Friday, December 18, 2015 at 7:40:30 PM UTC-5, Michael Black wrote:
>>
>>
>>> It's better to let someone else pay the full price for such things.  If I
>>> didn't find it cheap or free, I wouldn't be buying it new.
>>
>> I'm envious that you can find so much old electronic gear and
> they did decide it was time to move up once the ribbon got so expensive.
>
> It's easy to see DVD players waiting for the garbage, but mostly they have 
> no remote.  It makes me wonder if someone lost the remote, and then scraps 
> the DVD player.  Some of it has to be moving up to blu-ray, but maybe not 
> all.  On the other hand, it's not uncommon to see the remotes separately, 
> as if they've been found long after the equipment was discarded.  I even 
> once found a remote for the VCR I bought at a garage sale, so I had a 
> spare.
>

To combine threads, LEDs are a fun way of getting kids interested in
 Electronics. As a fun way of hobby for this child, got a minikit
for a thing called "TVbeGone" (or similiar) after soldering, nothing
would happen with my TV, anyway the directions said "US area only",
coming back from town, at a red light, there was a large TV showing in 
a window, so for fun, I pointed and clicked, and the TV went blank, and 
someone previously watching was trying with the remote.

I have a lot of remotes, a couple that can be adjusted. When the TV 
gets boring, its fun to try them out.



-- 
greymaus
 .
  .
...

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#155308

On Wed, Dec 16, 2015 at 02:23:34PM -0500, Michael Black wrote:
> On Wed, 16 Dec 2015, hancock4@bbs.cpcn.com wrote:
> 
> >On Tuesday, December 15, 2015 at 3:02:18 PM UTC-5, Michael Black wrote:
> >>Since the photocell dropped resistance with light, I initally couldn't
> >>figure out how that would work.  When the light wasn't interrupted, the
> >>photo cell would let the voltage from the battery to the bell (I was
> >>thinking in terms of "burglar alarm"), but it was when the light was
> >>interrupted that you needed the bell.
> >
> >I don't know the specific technology, but in the 1950s-1960s there
> >were two types of camera meters.  (Originally the meter was a
> >separate device, then later miniaturized to fit into the camera).
> >
> >Anyway, the earliest meters just measured the light and used it
> >to drive the meter scale.  I think it was plain photo cell.
> >
> An actual "solar cell".  But that would give the same problem, voltage 
> only when the light isn't interrupted.
> 
> >Later, better meters required a battery and used a different
> >photo cell (Cs?).  That measured the difference and was
> >supposedly more accurate.
> >
> Cadmium photocells, or something, they varied resistance with light, 
> rather than generating voltage.  That's what I had, and since the 
> resistance went up with the beam of light was broken, still not useful.
> 
> Like I said, it was early on in my learning about electronics, and at the 
> time I couldn't see a solution, though later I could.
> 
> 
> >My old Nikon required a tiny battery for the meter; everything
> >else was manual.  The meter battery lasted forever.  My
> >digital Nikon has a battery the size of the Empire State
> >Building and needs regular charging.  A replacement is $50.
> >
> The only good camera I had had batteries, but that also powered the
> built in flash.  I seem to recall it used two "N" cells, half the length 
> of an AA, and not so commonly available.  But the batteries did last long.
> 
> >(I suspect when that battery no longer holds a charge, a
> >replacement won't be available, and I'll have to buy a
> >whole new camera.  Admittedly, I do like digital better
> >than film, but the rapid obsolescence is a turnoff.)
> >
> I found a decent Olympus point and shoot, something like 6MP so it was 
> fine for most uses.  Even came with a 1gig memory card, useful since it 
> used XD cards. But it didn't use standard batteries, and I'm not willing 
> to spend the money on a new battery unless I know that the camera works, 
> and without the battery, I can't test the camera.
> 
> I'd never buy a new camera that didn't use AA batteries, so if I was 
> really stuck, I could put in alkaline bought at the corner store.
> 
> Of course, most digital cameras also have some button cells, to keep
> settings intact, and who knows what else.

Some consumer devices use serial memories for settings and the like,
others probably use nand flash chips with a bus interface.  It will
depend on the embedded architecture in actual use.  Things continue to
move quickly on that front.  I took apart a possibly 2005-ish vintage
LCD monitor once and found two low-capacity i2C serial flash devices
as well as a SPI serial flash chip. 1-4KB capacity if I recall
correctly.  I have difficulty imagining why they needed three and of
two bus varieties.

The 16550 LiON battery form-factor continues to be popular, but not
for most portable devices.  Many portable "power packs" use them, and
of course they ended up in zillions of laptop battery packs.  I think
they may be used in hybrid vehicles as well.  Some cameras,
particularly the compact hand-held point-and-shoot variety are too
small for that form factor, but a whole lot of DSLR cameras aren't.

It would be nice if there were more standardization on battery formats
for such things, but then that would interfere with planned
obsolescence.

LED flashlights which take 'AA' format batteries are fairly common,
and I have standardized personally on those models.  Flashlights have
now become a 'thing' and all the really snappy varieties use
high-quality 16550 rechargeables.  Mostly they seem optimized for
throw rather than endurance.  I once had a little one 'AA' task light
that was rated for 100 hours continuous operation on a standard
alkaline battery.  So of course someone stole it from my tool bag
while I was at work.  The replacement now lives in my pocket.



-- 
We all cannot be intelligent, but at least we can all be polite.

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#155242

Jon Elson <jmelson@wustl.edu> wrote:
> Quadibloc wrote:

>> On Friday, December 11, 2015 at 8:31:35 AM UTC-7, hanc...@bbs.cpcn.com
>> wrote:
>> 
>>> When I was young, the automatic doors in supermarkets were almost
>>> all controlled by a pressure-sensitive flood mat.  It was very
>>> rare to see a door controlled by photo cells.   I think today
>>> they use a motion sensor, not the floor mat.
>> 
>> I think the popular method is something called "passive infrared". Which
>> sounds like a heat sensor.
> No, there really were visible beam systems in use in the 1950's.  They had 
> heavy stainless bars and poles next to the doors, and if you got down low 
> you could see they had slots in the vertical poles.  One side of the "gate" 
> had an incandescent lamp and a lens in it, the other side had a vacuum 
> photodiode.  

I vaguely recall seeing something similar in operation in the 1980s.  
Incandescent detectors persisted until the late 1990s.  The emitter and 
detector were in a single unit and were aimed a retroreflector on the 
opposite side of the gate.

-- 
David Griffith
davidmylastname@acm.org   <--- Put my last name where it belongs

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#155272

Jon Elson <jmelson@wustl.edu> writes:

> Quadibloc wrote:
> 
>> On Friday, December 11, 2015 at 8:31:35 AM UTC-7, hanc...@bbs.cpcn.com
>> wrote:
>> 
>>> When I was young, the automatic doors in supermarkets were almost
>>> all controlled by a pressure-sensitive flood mat.  It was very
>>> rare to see a door controlled by photo cells.   I think today
>>> they use a motion sensor, not the floor mat.
>> 
>> I think the popular method is something called "passive infrared". Which
>> sounds like a heat sensor.
>
> No, there really were visible beam systems in use in the 1950's.  They had 
> heavy stainless bars and poles next to the doors, and if you got down low 
> you could see they had slots in the vertical poles.  One side of the "gate" 
> had an incandescent lamp and a lens in it, the other side had a vacuum 
> photodiode.  

There was one store in Concord, NH that had such a setup circa 1950.
I was quite taken with it as a smallish child but it was, sadly, a
store my mother visited only infrequently

MIT has a similar door opener for the big brass front doors on their
main building on Mass. Av.  I vaguely recall hearing that it was kept
in operation because it was the first one of its kind in regular use
and MIT was very proud of it.  Some MIT grad can perhaps supply the
historical facts?

-- 
Mike Spencer                  Nova Scotia, Canada

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#154973

hancock4@bbs.cpcn.com writes:
>Sylvania ran an ad for its LED back in 1957, called a photo diode.
>It was in C&A 09-1957, pg 19.

 Photo-diode != LED

one sends, one receives.

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#154984

"Scott Lurndal" <scott@slp53.sl.home> wrote in message 
news:m9kay.15466$qz7.15339@fx01.iad...
> hancock4@bbs.cpcn.com writes:
>>Sylvania ran an ad for its LED back in 1957, called a photo diode.
>>It was in C&A 09-1957, pg 19.
>
> Photo-diode != LED

Except that most LEDs are reciprocal to light of the same frequency.

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#154992

"gareth" <no.spam@thank.you.invalid> writes:

> "Scott Lurndal" <scott@slp53.sl.home> wrote in message 
> news:m9kay.15466$qz7.15339@fx01.iad...
>> hancock4@bbs.cpcn.com writes:
>>>Sylvania ran an ad for its LED back in 1957, called a photo diode.
>>>It was in C&A 09-1957, pg 19.
>>
>> Photo-diode != LED
>
> Except that most LEDs are reciprocal to light of the same frequency.

While that is technically true, LEDs have "awful" characteristics for
all of the important numbers that make a "good" photodiode.

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#155004

On Thu, 10 Dec 2015, gareth wrote:

> "Scott Lurndal" <scott@slp53.sl.home> wrote in message
> news:m9kay.15466$qz7.15339@fx01.iad...
>> hancock4@bbs.cpcn.com writes:
>>> Sylvania ran an ad for its LED back in 1957, called a photo diode.
>>> It was in C&A 09-1957, pg 19.
>>
>> Photo-diode != LED
>
> Except that most LEDs are reciprocal to light of the same frequency.
>
But does that work both ways?

I know people have seen problems with semiconductor diodes that pick up 
light from a nearby lightbulb.  And certainly you can use an LED as a 
receiver of light, though I suspect it's not too efficient.

But can you put light through a diode not intended to generate light, and 
get light?

   Michael

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#155010

In article <alpine.LNX.2.02.1512102259410.27954@darkstar.example.org>,
 Michael Black <et472@ncf.ca> wrote:

> On Thu, 10 Dec 2015, gareth wrote:
> 
> > "Scott Lurndal" <scott@slp53.sl.home> wrote in message
> > news:m9kay.15466$qz7.15339@fx01.iad...
> >> hancock4@bbs.cpcn.com writes:
> >>> Sylvania ran an ad for its LED back in 1957, called a photo diode.
> >>> It was in C&A 09-1957, pg 19.
> >>
> >> Photo-diode != LED
> >
> > Except that most LEDs are reciprocal to light of the same frequency.
> >
> But does that work both ways?
> 
> I know people have seen problems with semiconductor diodes that pick up 
> light from a nearby lightbulb.  And certainly you can use an LED as a 
> receiver of light, though I suspect it's not too efficient.
> 
> But can you put light through a diode not intended to generate light, and 
> get light?

Yes. Briefly.     8^}

Isaac

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#155012

On Thu, 10 Dec 2015 21:21:14 -0800, isw <isw@witzend.com> wrote:
> In article <alpine.LNX.2.02.1512102259410.27954@darkstar.example.org>,
>  Michael Black <et472@ncf.ca> wrote:
>
>> On Thu, 10 Dec 2015, gareth wrote:
>> 
>> > "Scott Lurndal" <scott@slp53.sl.home> wrote in message
>> > news:m9kay.15466$qz7.15339@fx01.iad...
>> >> hancock4@bbs.cpcn.com writes:
>> >>> Sylvania ran an ad for its LED back in 1957, called a photo diode.
>> >>> It was in C&A 09-1957, pg 19.
>> >>
>> >> Photo-diode != LED
>> >
>> > Except that most LEDs are reciprocal to light of the same frequency.
>> >
>> But does that work both ways?
>> 
>> I know people have seen problems with semiconductor diodes that pick up 
>> light from a nearby lightbulb.  And certainly you can use an LED as a 
>> receiver of light, though I suspect it's not too efficient.
>> 
>> But can you put light through a diode not intended to generate light, and 
>> get light?
>
> Yes. Briefly.     8^}
>
> Isaac

Cue old magazine article about a Noise Emmiting Diode :-)

-- 
Stan Barr     plan.b@bluesomatic.org

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#155051

On Fri, 11 Dec 2015, Stan Barr wrote:

> On Thu, 10 Dec 2015 21:21:14 -0800, isw <isw@witzend.com> wrote:
>> In article <alpine.LNX.2.02.1512102259410.27954@darkstar.example.org>,
>>  Michael Black <et472@ncf.ca> wrote:
>>
>>> On Thu, 10 Dec 2015, gareth wrote:
>>>
>>>> "Scott Lurndal" <scott@slp53.sl.home> wrote in message
>>>> news:m9kay.15466$qz7.15339@fx01.iad...
>>>>> hancock4@bbs.cpcn.com writes:
>>>>>> Sylvania ran an ad for its LED back in 1957, called a photo diode.
>>>>>> It was in C&A 09-1957, pg 19.
>>>>>
>>>>> Photo-diode != LED
>>>>
>>>> Except that most LEDs are reciprocal to light of the same frequency.
>>>>
>>> But does that work both ways?
>>>
>>> I know people have seen problems with semiconductor diodes that pick up
>>> light from a nearby lightbulb.  And certainly you can use an LED as a
>>> receiver of light, though I suspect it's not too efficient.
>>>
>>> But can you put light through a diode not intended to generate light, and
>>> get light?
>>
>> Yes. Briefly.     8^}
>>
>> Isaac
>
> Cue old magazine article about a Noise Emmiting Diode :-)
>
I had some of those. I was using them in a power supply, and put at least 
one in backwards.  There was a bang, and shreds of epoxy exploded into the 
room.

    Michael

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#155070

"Stan Barr" <plan.b@bluesomatic.org> wrote in message 
news:slrnn6l0nl.8tc.plan.b@ID-309335.user.uni-berlin.de...
> On Thu, 10 Dec 2015 21:21:14 -0800, isw <isw@witzend.com> wrote:
>> In article <alpine.LNX.2.02.1512102259410.27954@darkstar.example.org>,
>>  Michael Black <et472@ncf.ca> wrote:
>>
>>> On Thu, 10 Dec 2015, gareth wrote:
>>>
>>> > "Scott Lurndal" <scott@slp53.sl.home> wrote in message
>>> > news:m9kay.15466$qz7.15339@fx01.iad...
>>> >> hancock4@bbs.cpcn.com writes:
>>> >>> Sylvania ran an ad for its LED back in 1957, called a photo diode.
>>> >>> It was in C&A 09-1957, pg 19.
>>> >>
>>> >> Photo-diode != LED
>>> >
>>> > Except that most LEDs are reciprocal to light of the same frequency.
>>> >
>>> But does that work both ways?
>>>
>>> I know people have seen problems with semiconductor diodes that pick up
>>> light from a nearby lightbulb.  And certainly you can use an LED as a
>>> receiver of light, though I suspect it's not too efficient.
>>>
>>> But can you put light through a diode not intended to generate light, 
>>> and
>>> get light?
>>
>> Yes. Briefly.     8^}
>>
>> Isaac
>
> Cue old magazine article about a Noise Emmiting Diode :-)
>

And don't forget the "magic smoke".  After you let the "magic smoke" out of 
a circuit component, the component has been munged and is *no* good 
anymore!!! :-(

-- 

numerist at aquaporin4 dot com

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#155092

On Fri, 11 Dec 2015 15:36:50 -0600, Charles Richmond 
<numerist@aquaporin4.com> wrote:
>
> And don't forget the "magic smoke".  After you let the "magic smoke" out of 
> a circuit component, the component has been munged and is *no* good 
> anymore!!! :-(

My Racal RA1792 comms receiver let the magic smoke out (again!) the
other day.  The dreaded tantalum caps strike again... :-(

-- 
Stan Barr     plan.b@bluesomatic.org

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#155096

On 2015-12-12, Stan Barr <plan.b@bluesomatic.org> wrote:
> On Fri, 11 Dec 2015 15:36:50 -0600, Charles Richmond 
><numerist@aquaporin4.com> wrote:
>>
>> And don't forget the "magic smoke".  After you let the "magic smoke" out of 
>> a circuit component, the component has been munged and is *no* good 
>> anymore!!! :-(
>
> My Racal RA1792 comms receiver let the magic smoke out (again!) the
> other day.  The dreaded tantalum caps strike again... :-(
>
Are replacements available?


-- 
greymaus
 .
  .
...

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#155103

On 12 Dec 2015 11:20:36 GMT, mausg@mail.com <mausg@mail.com> wrote:
> On 2015-12-12, Stan Barr <plan.b@bluesomatic.org> wrote:
>> On Fri, 11 Dec 2015 15:36:50 -0600, Charles Richmond 
>><numerist@aquaporin4.com> wrote:
>>>
>>> And don't forget the "magic smoke".  After you let the "magic smoke" out of 
>>> a circuit component, the component has been munged and is *no* good 
>>> anymore!!! :-(
>>
>> My Racal RA1792 comms receiver let the magic smoke out (again!) the
>> other day.  The dreaded tantalum caps strike again... :-(
>>
> Are replacements available?
>
>

I just replace them with standard electrolytics, which is what most
people do.  It's just that there a dozens on each board in a mix of
values and often very small sizes.  I replace the lot while I've got
the board out, a real pain!

The old valve Racal, however, just keeps soldiering on...there's a 
lot to be said for old technology!

-- 
Stan Barr     plan.b@bluesomatic.org

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#155106

On Sat, 12 Dec 2015, mausg@mail.com wrote:

> On 2015-12-12, Stan Barr <plan.b@bluesomatic.org> wrote:
>> On Fri, 11 Dec 2015 15:36:50 -0600, Charles Richmond
>> <numerist@aquaporin4.com> wrote:
>>>
>>> And don't forget the "magic smoke".  After you let the "magic smoke" out of
>>> a circuit component, the component has been munged and is *no* good
>>> anymore!!! :-(
>>
>> My Racal RA1792 comms receiver let the magic smoke out (again!) the
>> other day.  The dreaded tantalum caps strike again... :-(
>>
> Are replacements available?
>
You can't get more generic than capacitors.  But it can be tedious, people 
will often replace them all because once one goes, likely others of the 
same vintage will go soon enough.  If you have the radio open, might as 
well change them all together.  I don't know about this Racal, but some 
receivers are legendary in being really difficult to get to all the places 
that need replacement capacitors (which is another good reason to change 
them all once you are working on the radio).

   Michael

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