L E D's Dual brightness

[cabur]

I was following a G35 and was wondering how the tail light cluster can change brightness (intensity) on the same L E D?
Is it voltage or circuit change. Just wondering?

[x8dragon8x]

it kinda sounds like how our drls are. during the day the highbeams use less voltage and when you turn them on, they get the full amount of voltage to power them.

[XRSized]

Pulse Width Modulation (PWM)
http://en.wikipedia.org/wiki/Pulse-width_modulation

[nate89]

Originally Posted by XRSized

Pulse Width Modulation (PWM)
http://en.wikipedia.org/wiki/Pulse-width_modulation

Exactly what I was gonna say.

You could also have two positive wires going to the anode (with diodes to prevent current from flowing backwards) with two different resistors. For low light output, the current flows through the wire with the higher resistance. Then for high light out but, current flows through the wire with high resistance and the wire with low resistance. That's how a lot of guys who do diy led conversions do it (without paying $$ for a PWM).

[CraigW]

PWM is correct.

Has anyone noticed that certain models using the LED tail and brake lights really mess with you if you look at them for any length of time ??

It has something to do with the frequency of PWM that is used being too low.

[nate89]

Nope. I keep my eyes on the road when I drive

[XRSized]

Never noticed that. I had own boards in my maxima's tail lights with the dimmer switch for the running lights. They worked great. I wonder how the corolla led tail lights have the dim/bright setting controlled.

[SuperchargedMR2]

Originally Posted by XRSized

Pulse Width Modulation (PWM)
http://en.wikipedia.org/wiki/Pulse-width_modulation

Now there's a term that got drilled into my head when I went into radiography.