LEDs: rheostat - bad, PWM controller - good - Saab 900 Bulletin Board - Saabnet.com
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LEDs: rheostat - bad, PWM controller - good
Posted by Siegfried (more from Siegfried) on Tue, 8 May 2012 15:09:12
In Reply to: Re: Cluster lights, Landjet [Profile/Gallery]
, Tue, 8 May 2012 14:21:08
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Landy,
LEDs should be better driven with a given optimum current and if you need to adjust the output (flux) then you better add a PWM controller into the circuit.
PWM isn't that frightful as it first sounds. This acronym stands for Pulse-Width Modulation, i.e. imagine yourself giving a push to your saab (I know your saabs do not need that, but try imagine something like that). If you're continuously pushing it, then we can say you're applying your force at 100% PWM ratio. If you're not touching it at all, then it's like 0% PWM. Then let's move a bit further and consider it's a bad and really naughty saab and you're kicking it at... say 1Hz (= once a second). If you're applying your force every 1/2 second and resting the other half of second, then it's 50% PWM drive. If you're applying your force every 1/4 of second and having a rest for remaining 3/4 of second, then it is 25%. If you're working hard and are applying your force for 0.75 second and having a rest only for remaining 0.25, then you're driving it (ok, giving a push) at 75% PWM ratio (or level).
You can find assembled PWM controllers handing 12+ Volt for about ~$10 on that famous bay site.
Alles gut,
Zig
posted by 188.134.44...
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