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  • Using resistors

    I 'm making a ir receiver for which i found the schematics in the web . i need a resistor of a value i cant find can i add other resistor up to that value and if yes is there a polarity i should respect ?
    Apple Ipod 20gig 4th gen black and white. Saves you lots of time. and a pocketpc with wifi for the ocasional email cheking and mapping at a hotspot.

  • #2
    basic electronics:

    resistors in series (one after another):
    R(total) = R(1) + R(2)

    resistors in parallel (side by side, with their lead connected):
    1/R(total) = 1/R(1) + 1/R(2)
    or
    R(total) = {R(1)*R(2)} / {R(1)+R(2)}

    someone PLEASE correct me if im wrong.

    also, the equations can be continnued for more than 2 resistors, although the second eq for the parallel gets pretty hairy. just use the first one (for parallel) and a calculator!! the series one is always easy.

    oh, and the equations are switched for capacitors.

    ~mike
    Single Member of the "1000 Post and No MP3 Car" Club
    PROJECT ON INDEFINATE HOLD... BOUGHT A HOUSE
    2000 Cavalier Z24 [###-------] Only 30% Done ... Still

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    • #3
      someone PLEASE correct me if im wrong.
      you are correct.

      resistors is parallel are strange things.

      On another note does any one know a site with the chart to tell you what coloured bands you need for a particular resistance??

      hornet
      http://www.mp3vl.tk Plans and progress on my install - (Updated 28 June 02)
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      • #4
        Originally posted by hornet
        On another note does any one know a site with the chart to tell you what coloured bands you need for a particular resistance?
        No but

        0 = Black
        1 = Brown
        2 = Red
        3 = Orange
        4 = Yellow
        5 = Green
        6 = Blue
        7 = Purple / Violet
        8 = Grey or White (can't rember which but nobody uses 8)
        9 = Grey or White (can't rember which but nobody uses 8)

        The first 2 or 3 (depends on the resistor) colour bands are the first 2 0r 3 numbers in the value and the last band is the number of zeros.

        I think an example might help

        red red yellow would be 220000 ohms or 220k ohms
        yellow purple black red would be 47000 ohms or 47k ohms

        The odd colour on it's own normaly gold or silver is the tolerance, just ignor it.

        I cann't rember which way round you read the colour bands, but one way makes sense and the other doesn't.

        I hope that make sense, rather than confussing things.

        Rob

        PS. Does any one know which is 8 & which is 9
        And you say people actually pay money for M$ Windows?
        www.mp3mini.co.uk (Does what it says on the URL) www.openclassic.co.uk (The new car, with zero rust!) www.rob-web.co.uk (My other site)
        Total re-design underway: on the whole progress is very slow as the car is taking up too much time :)

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        • #5
          8 grey
          9 white
          If you come out talking sh1t don't try to turn around and wipe you azz.

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          • #6
            this calculator is pretty handy if you are working near a computer.

            ~mike
            Single Member of the "1000 Post and No MP3 Car" Club
            PROJECT ON INDEFINATE HOLD... BOUGHT A HOUSE
            2000 Cavalier Z24 [###-------] Only 30% Done ... Still

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            • #7
              mp3z24,
              Man, that calculator and that entire site, rocks!

              I can't get over the stuff you can do with Java.
              Wellfooled
              Workin' on an mp3 Sequoia

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              • #8
                Solder a small pot, adjust it, then use a drop of superglue to permanetly fix it's value.

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