AC driven LED resistor value error

Discussion in 'Feedback and Suggestions' started by belisarius, Dec 26, 2008.

  1. belisarius

    Thread Starter New Member

    Dec 24, 2008
    2
    0
    I searched the forums and didn't find this mentioned; my apologies if it is a duplicate.

    In the LED section of Vol. III, section 3.12 ("Figure 3.72: Safely driving an LED with AC: (a) from 24 VAC, (b) from 240 VAC.", pg 158 in the PDF), there is a circuit for driving an LED from a 240VAC source, and the text mentions a 12K ohm resistor, but the circuit drawing has a 1.2K ohm resistor.
     
    Last edited: Dec 26, 2008
  2. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    If the led can withstand a peak current of about 26mA you can use a 12K resistor. Otherwise use 16K resistor.
     
  3. belisarius

    Thread Starter New Member

    Dec 24, 2008
    2
    0
    Thanks. I just re-read that section and noticed that it has the capacitor in place, which means the 1.2K is correct for that drawing. D'oh! As Chief Wiggum would say, "Move along, nothing to see here."
     
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