06/23/2003 06:39:02 PM
All that you say is true under those circumstances.
Another approach might be:
no more than 2 leds in series since if one goes, they
all stay dark
I put bypass caps on anything with sharp transitions,
and we are talking 10
4 harmonics to the nav/com
range
Course, ADF would be more likely affected, but I
would not consider putting such an Antique Direction
Flubber in my plane ;-)
> Yes super bright LEDs are available, too bright for me to look at when
> on with 15 ma, but they do get brighter still with pulsing. I don't think
> 10 kHz is going to interfere with much on an aircraft.
>
> Ira N224XS in paint shop
I wouldn't bet on that! A square wave is the fundamental freq plus the
sum of all harmonics, each 3dB down I recall. If used to pulse a series
string of LEDs, and say a voltage swing of 10V, you can easily get a few
microvolts in the harmonics to annoy a VHF receiver whose antenna is a
few feet away.
Fred F.
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