Quote:
Originally Posted by troypiggo
Thanks mate.
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Troy, where abouts in Brisbane are you?
Also, all three resistors look different to me, if you type out the colours here I can tell you their values.
FYI RS components is free overnight shipping for any order (confirm for single resistor, but should be free), probs be way cheaper than Jaycar.
FYI Soanarplus is supplier for Jaycar and uses the same catalogue numbers. Shipping cost works such that best to buy a few things at a time, not just one resistor.
Assume a 10mA forward current @ 3v forward voltage (conservative) and use this calculator to calculate appropriate resistor value:
http://led.linear1.org/1led.wiz
If LEDs are in series, multiply 3v forward voltage by number of LEDs. If LEDs are in parallel, multiply 10mA forward current by number of LEDs. Ideally, each LED has its own resistor.
just FYI.
However, you can use resistors they have used and multiply by a factor to reduce brightness. Eg if you want half as bright (Theoretical), simply double the resistor values they have used. That way you can avoid the led calculator altogether.
I say theoretical because eye response to brightness is logarithmic
