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  1. #1
    150+ Forum Groupie BishBash's Avatar
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    what resistor do i need

    I have glb flight landing gear lever for 737 and it has an led for the knob which
    requires 5v supply and resistor.
    I will connect to a cpu 5v power supply but not sure what resistor i need.

    Any help please men

    Thanks

    steve
    Last edited by BishBash; 04-22-2011 at 04:52 AM. Reason: spelling

  2. #2
    500+ This must be a daytime job Sean Nixon's Avatar
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    Re: what resistor do i need

    R = (Vs-Vl)/I

    R = resistor size
    Vs = supply voltage (5v in your case)
    Vl = LED voltage (check this, if you're saying 5v, then the result equals zero)
    I = LED current (usually 10 or 20mA (0.01 or 0.02A)

    If you can't determine the values needed, go for a higher resistor and work down. Maybe try somewhere around 300 ohms first?

    R = (5-2)/0.01 = 300

  3. #3
    150+ Forum Groupie BishBash's Avatar
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    Re: what resistor do i need

    Sorted,went with 330.

  4. #4
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    Re: what resistor do i need

    Generally LED's are 2.2 - 2.6 volt devices and so we need to limit current on a 5V supply general good starting point is 330Ohms resistor
    color code orange - orange - brown
    then adjust up or down to get the light intensity you require - just be aware some LED's are low light efficiency if viewing from the side and so dont reduce resistor too far
    hold on steve - I recognise you now and I know this is is solved - will leave the reply in for other members

  5. #5
    150+ Forum Groupie BishBash's Avatar
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    Re: what resistor do i need

    Quote Originally Posted by UKV1342 View Post
    Generally LED's are 2.2 - 2.6 volt devices and so we need to limit current on a 5V supply general good starting point is 330Ohms resistor
    color code orange - orange - brown
    then adjust up or down to get the light intensity you require - just be aware some LED's are low light efficiency if viewing from the side and so dont reduce resistor too far
    hold on steve - I recognise you now and I know this is is solved - will leave the reply in for other members
    Thanks Mike,
    Yes I got the right resistor off Derek (flyuk) after my chat with yourself and derek,not forgetting young seans
    advise here too.
    Regards
    Steve UKV1566