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Electronics WTF? a led off a ccfl converter?

Discussion in 'Modding' started by korhojoa, 16 Apr 2004.

  1. korhojoa

    korhojoa durr

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    yea, that's what i'm doing, i run a green led off a ccfl converter.

    whoa, it arcs whenever you connect the legs to the converter, and i thought that i'd get a really, really, really cool effect if i tried this (as like in the Led death post in the disaster section), but to my astonishment, the bloody thing just works, and the led is as happy as ever, weird.

    Can anyone tell me why the led is still alive? dunno what kinda voltage the sucka puts out, but it says on the sticker "Warning High Voltage" so dunno, maybe ~1000 volts?

    [​IMG]
     
  2. kenshin

    kenshin Banned

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    That led should be dead.... :eyebrow:.... a ccfl inverter normally gives out around 10k iirc
     
  3. TheAnimus

    TheAnimus Banned

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    with LEDs its current thats the killer not voltage.

    The LED will still drop the same amount of voltage at 1000v as it would at 5v.
    LEDs don't mind PWM either.
    Indeed if it was a standard voltage source, odds are you would kill the voltage source, but most CCFL controllers are designed to kick start at 1000v then reduce to a running voltage (normally around 300v).

    So be careful you don't burn out the controller.
     
  4. Smilodon

    Smilodon The Antagonist

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    have you tried to run the LED on the voltage it's made for again?

    my theory is that the LED might be damaged (the thin wire that runs from the anode to the die is burned off)... however, when you apply high voltage this is enough to make the current "jump" over without any wire...

    i did something similar once: i connected a led to the igniter (piezo) that sits in lighters... when you press the button you will get a flash in the LED...
     
  5. SteveyG

    SteveyG Electromodder

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    The inverter may not be able to supply enough current to damage the LED quickly, though I'm sure it'll stop working over time.

    Time for you to get out the test meter and take some readings.
     
  6. korhojoa

    korhojoa durr

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    The led still works using the normal voltage, and i've too tried that piezo lighter thingy on a bright white led, amazingly it survived. :hehe:

    And about the controller, no problem, i don't have a ccfl for it so i can burn it without problems. The led sure got yellow after using the converter for like 15 mins, but when i shut the converter off, and then back on again, it was fine. :confused:

    Done some nice arcs too with the converter :) i love the smell of ozone in the morning, aaah... :D
     
  7. ConKbot of Doom

    ConKbot of Doom Minimodder

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    I hooked a car coil to a relay set up to buzz, and a cap, I could get a 2cm arc from it, and hooked up 4 leds to it, and had a nice pulsing glow from the leds.
     
  8. kbn

    kbn What's a Dremel?

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    I ran an inverter without the case and multimeter said the ccfl was at 1.8kv!
    how much current do you think it supplys, was going to touch it on one finger with another finger (SAME HAND!) to ground :D but decided it probably would be too much current to be safe. Dont ask me why i was going to... thought it might be fun :p
     
  9. TheAnimus

    TheAnimus Banned

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    most are around 2ma.

    Hook the invertor's power feed up, work out the whatts, then from P=IV you can calculate the max possible current.
     
  10. ConKbot of Doom

    ConKbot of Doom Minimodder

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    I know one thing, that car coil had a but of a punch to it, (I was discharging a 500 uf cap into the primary coil) I accidentialy got zapped and my hand was odd feeling for about 30 mins, not numb, just kind of strange.

    But then the coil was probably putting out more than 1.8 kv. I can't remember how to hook up the cap, relay, and coil now, so no more high voltage for me. (anyone else know how to do it? :D )

    The CCFL inverter shouldnt hurt too bad. :hehe:
     
  11. TheAnimus

    TheAnimus Banned

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    CCFL inerters nip no more than an electric fence, but you never know u might have a weak heart.
     
  12. SteveyG

    SteveyG Electromodder

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    I made a very simple driver for ignition coils when I was about 14. I could strike 1 to 1.5" arcs from the coil and draw it out to probably double. Air breakdown is about 1.1kV/mm iirc, so thats over 25kV.

    If you use a 555 set to high frequency (i'll test the freq in a min) and a big transistor you can drive the coil from that and since it's HF you'll get a nice purple arc as opposed to sparks.

    If you want to use the relay method, use a DPDT relay, and arrange the coil and one set of contacts so that when the relay turns on it disconnects the coil turning it off, which then closes the contacts turning the coil on and so on. Then connect the ignition coil's +ve to one of the other contacts with a 12V supply to the common from that set of contacts. Use a beefy PSU for higher current sparks, or crack the voltage up to 24/48V for longer (higher voltage) sparks.

    /edit.
    Frequency of 555 driver was 4.5kHz, but use variable resistors to change frequency and also duty cycle for different effects.

    I believe there's another method of using a dimmer switch connected to the mains driving the coil through a capacitor, though I didn't have any dimmer switches to try this.
     
    Last edited: 17 Apr 2004
  13. ConKbot of Doom

    ConKbot of Doom Minimodder

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    That sounds about right, and the HF would definitely work great.

    In my welding class, we take the tig machine, turn on the HF start and have a person hold a filler rod. We strike an arc on the rod and there is enough capacitive coupling through their boots into the concrete, and into the table which is grounded to get a skinny little 2" arc after you start pulling it out.

    Though one I leaned against the wall of the booth :wallbash: , and there was some exposed metal (the paint chipped off) and that was touching the table, so I got a nice buzz from that.
     
  14. korhojoa

    korhojoa durr

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    *orders huge caps from online retailers* *orders lots of heavy duty powersupplies* *gets killed by ~400kV arc* :D
     

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