Date: Thu Nov 30 19:29:57 2006 Back to Contents

Author: cablem

Subject: Re: Cars, lights, and mileage - was Re: The

Your eye's sensitivity to the pulsing is more pronounced on your
peripheral vision than in your direct. That way, we detect an ambush
from the side better. Sounds good, anyway.


On 11/30/2006 5:03 PM, Krishna Chowdary wrote:
> On 11/30/06, Gerald Zani wrote:
>> LED lights are more efficient when driven with pulsed DC rather than
>> pure
>> DC. They run cooler and brighter when driven with pulses. Depending
>> on the
>> LED color some LED lights are driven at a frequency somewhere between
>> 10 and
>> 20 kHz pulsed DC.
>> LED lights, including flashlights, today use a programmable, embedded
>> microprocessor integrated in the lamp to control the pulses, and to
>> adjust
>> the pulse frequency and the pulse duty cycle for changes in the battery
>> power to better maximize the lamp efficiency when the battery gets low.
>> That is why they flicker.
> Thanks for the info! I wouldn't think that people would notice 10 kHz
> pulsing, but maybe the pulse rate is a lot lower in cars. Anybody
> know how
> I could find that info out? I couldn't stumble on the right set of
> keywords. I'm wondering if this might be a cheap alternative to
> strobes...

Machele Kindle
Lab Manager
Physics Dept.
Wake Forest University
Winston-Salem, NC 27109

Phone: 336-758-5532
Fax: 336-758-6142

"Get Fuzzy"

Bucky, the arrogant cat: Aaaaaaaa!

Rob, the geeky owner: 11:55. Right on time for his nightly freakout.

Satchet, the lovable dog: Ever notice how he runs circles in the same direction?

Buckey: Yaaaaaaaa!

Rob: Maybe the coriolis effect works on cats, too, eh?

Satchet: Ha, ha! I have NO idea what that means!

From Thu Nov 30 19:29:57 2006