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When did LEDs become common?

Discussion in 'General Electronics Chat' started by Triode, Sep 20, 2017.

  1. Triode

    Triode Member

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    This is just a question of curiosity. I can look up on wikipedia when LEDs reached various milestones, but the cost and efficiency curves are nearly linear, for example:

    [​IMG]
    I also found this line, which seems to mark a possible point where they went from an expensive new technology to something you could add on as an indicator without worries about cost:

    "In the 1970s commercially successful LED devices at less than five cents each were produced by Fairchild Optoelectronics."

    I can't find data for the number of LEDs sold per year, mostly because results are clouded by charts of sales of LED TVs and other related technologies.

    Given the chart and the quote about Fairchild I would guess 1974 or thereabouts is when you would have started to see LEDs used as indicators commonly. But when trying to confirm this by looking up computers, TVs and remote controls from 1975 I didn't spot a lot of LEDs. Even this IBM PC from 1975 doesn't seem to have any as a power indicator or on the disc drive. I would expect if any were in use you would see them there as these were fairly high cost machines.

    [​IMG]

    This question just came up in my mind because I was looking at a robot we were working on and with it's shells off it looks like a Christmas tree, every board has several LEDs to indicate communication and power are working. All together probably over 100. I'm just curious from those of you who were there when the transition happened when it seemed to come into common use.
     
    Last edited: Sep 20, 2017
  2. JimB

    JimB Super Moderator Most Helpful Member

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    From my own experience:

    1975 - Quite rare, never seen one (I think).
    1978 - Quite common on new equipment, both as simple power or status indicators, and 7 segment displays.
    1980 - Very common.

    JimB
     
  3. OBW0549

    OBW0549 Member

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    I don't think they enjoyed widespread usage until about the late 1970's or early 1980's, largely because they produced so little light. I still have a couple of green LEDs from back in the mid-1970's and they're so dim they need 20 mA forward current just to be visible in normal room lighting. At that current, a modern green "ultrabright" LED is so brilliant it's actually painful to look at.
     
  4. dave

    Dave New Member

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  5. ericgibbs

    ericgibbs Well-Known Member Most Helpful Member

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    hi,
    Using 'dim' Red and Green LED's in 1975.

    Slightly off topic, built a home outside security beam in 1977 using an IR LED emitter, path length 6 mtrs, pulsing at 500pps, 50mA, it is still running with no problems.!
    I make that approx 630,720,000,000 pulses in 40 years of operation.
    E
     
  6. schmitt trigger

    schmitt trigger Active Member

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    Well, I had a Texas Instruments SR51 calculator, back in 1974, which used tiny 7 segment red LEDs.
    Later that year I got a digital alarm clock kit, which also used a little larger 7 segment red LEDs.

    I clearly remember those dates, because that is when I entered college. I required the calculator for solving my engineering assignments, and the alarm clock to wake up in the morning!

    The first time I actually saw a LED in consumer electronics was in a Sony reel-to-reel tape recorder, perhaps next year.. The "Record" indicator was a red LED, but interestingly, the VU meters were still incandescent-lighted.
     
  7. Little Ghostman

    Little Ghostman Well-Known Member Most Helpful Member

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    1080 big growth in common use............ So how do I know? Cos i got a couple of very old computers my dad had as a kid, a pet 80, a zx80 and a commodore vic 20. The Pet 80 didnt have a led on it (his hasnt anyway), but that was early 1980, the others do have leds and are late 1980 (date code says November). I found a nerdy site on old computers, so it would seem reasonable that leds followed the computer path. Looking at sales of the Vic20 and the commodore 64, it seems it only took a couple of years to really start burning.

    But that is all I could find out, and i wasnt around that long ago. Interesting blip around 1975 on your graph.
     
  8. Little Ghostman

    Little Ghostman Well-Known Member Most Helpful Member

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  9. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    1974 ish for sure. I'm thinking 1972. It's about the time the National MM5311, MM5314 clock chips came out. The LED calculators came out somewhere between 1972 and 1975. It took a while to make a blue LED.
     
  10. ronsimpson

    ronsimpson Well-Known Member Most Helpful Member

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    Does any one have this graph going out to 2017?
    In about 1980 we got enough light out of red LEDs that I designed and sold out-door LED advertising signs. I have some of those very costly LEDs and they seem dim today.
    At the right hand side of the chart I was doing LED monitors/TVs and torches/flash lights. Today those torches will put your eye out and run for a month on batteries.
    upload_2017-9-21_20-5-22.png
     
  11. AnalogKid

    AnalogKid Well-Known Member

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    Those floppy disk drives did not have a power on LED, but they did have an in-use LED. Same for the 3-1/2" floppy drives that came later.

    Also, the IBM PC was introduced in August, 1981.

    ak
     
  12. RODALCO

    RODALCO Well-Known Member

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    I bought my first LED's in 1974. You could buy a packet of 16 LED's green, orange, yellow and red for 8 Guilders in The Netherlands. They needed 20mA and are very dim compared to today's standards. But they are still going 43 years later. I fitted some in a power supply which is on 24/7 and still going. Still have some of these classics too, will dig them up.
     

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