Quote:
Originally Posted by rida125
ok so in the guages, if im working with raw LED's, do i need to put in resistors with them, or does that whole system work on one circuit so i dont need to put resistors in?
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well, what line are you tapping/how are you getting power? if you wire them in series so that the LED forward voltage meets and adds up to the supply 12V, then you do NOT need a resistor, if you do say, a series like this
this is an example from my glow Needles
RED LED's
Forward Voltage @ 2.8V, 3.2 MAX @ 20mA
i have three LEDS in series off a 12V circut, i have two of these setups for the Speed and tach needles, so i have
2.8 X 3 = 8.4 Forward Volts, on a 12V circut, so i need to resist to 12V
(i left and used the lowest FV on the LED, so surges to 13.2 could be tolerated without blowout, and light Surging)
so,
8.4FV, @ 20mA, on a 12V circuit means you need a 330ohm 1/8th watt resistor and etc..
if you used a system like this,
2.8FV X 4 = 11.2V, with room for surging with 13.6 MAX V without a resistor, (that is the highest surge i have ever seen with any interior light)
so for the above, you do NOT need a resistor