LED bulbs

Discussion in 'General Motoring' started by D Nieves, Dec 3, 2003.

  1. D Nieves

    D Nieves Guest

    Has anybody purchased LED side marker and brake lights for their Hyundais?
    I'm thinking about it but I want to know if they'll fit into an Elantra GT's
    openings and if the brightness is comparable or better than an incandescent
    bulb? I found one place that has them in various colors
    http://shop.autoi.com/osb/showitem.cfm/Category/24 (supplier:
    http://www.lampbulbs.com.tw/New/New1.htm ) but ~$25 per LED bulb that should
    outlast a regular bulb that may not be a bright could become expensive if
    you consider replacing every light.
     
    D Nieves, Dec 3, 2003
    #1
  2. D Nieves

    Peter Lowrie Guest

    That's a bit expensive isn't it. Have you considered shopping for LED's
    online in say, the Philipenes - all components Waaay cheaper.

    If you connect them straight up you'll blow them up. You'll need a voltage
    divider of about 240 ohms: one resistor across the LED(s) in parallel and
    in series with the positive supply. http://www.jaycar.com.au sell them as a
    kitset that uses a hybrid PCB connected to the usual bayonette.

    I'm trying to flick-on intellectual property rights for my LED Accelerator
    at: http://www.geocities.com/ledaccelerator/9p/index.html .

    To answer your other questions. LED's make far better indicators, tail and
    brake lights than incandescent bulbs do. Provided you get your voltage
    divider (see an auto electrician) right they'll last 20000 hours plus. Good
    luck with your mods.

    2c
    PEL
     
    Peter Lowrie, Dec 6, 2003
    #2
  3. D Nieves

    nothermark Guest

    1. The LED needs a series current limiting resistor, nothing in
    parallel. Don't forget the wattage requirement on the resistor.

    2. The LED's in the catalog may not (probably will not) meet DOT
    brightess requirements.

    3. Your LED accelerator looks like snake oil. It's nothing more than
    a pulse modulator of some form (there are a few). The last time I
    looked at LED spec's one did not gain much with this type of
    regulation. Maybe the laws of physics changed since then.

    4. Looks like a lot of whor and money for an bulb that cost a buck
    and lasts years.
     
    nothermark, Dec 6, 2003
    #3
  4. D Nieves

    Peter Lowrie Guest

    Dear Nothermark

    A voltage divider needs two resistors to function properly. Electronics 101
    taught me that one is in series and the other in parallel. What's wrong
    with that?...Absolutely nothing. Otherwise it wouldn't be a divider but
    simply a load.

    2c
    PEL
     
    Peter Lowrie, Dec 6, 2003
    #4
  5. D Nieves

    nothermark Guest

    You don''t need a voltage divider - you need a current limiting
    resistor. The voltage accross the LED is not an issue as long as it
    is sufficent to forward bias the junction (turn it on) but not so high
    it blows it out. The problem is the current flow through the diode
    junction. The value of the resistor is approximately the system
    supply voltage - 1.5 divided by the operating current of the LED.
    The LED acts like a voltage regulator and sets the voltage accross the
    shunt resistor. The characteristic voltage drop accross a forward
    biased junction is essentially flat for a wide range of current. All
    the shunt resistor does is draw more load current throught the series
    resistor. You are not dealing with an electronics 101 circuit. It's
    around 103 depending on the curriculum. ;-)
     
    nothermark, Dec 7, 2003
    #5
  6. D Nieves

    Peter Lowrie Guest

    Ok, valid point noted, and I concur.

    2c
    PEL of
    http://www.geocities.com/ledaccelerator/9p/ fame.
     
    Peter Lowrie, Dec 7, 2003
    #6
Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.