1. Home
  2. Electronics Design
  3. Where's the inductor?
  4. Page 2

Where's the inductor?

The first time I saw that I was merging onto an unfamiliar road with one car going by. I returned my eyes to in front of me and suddenly my peripheral vision saw a dozen car taillights to my left. There is a huge instinct for self preservation and it set of a serious alarm!

That was a Cadillac and many others do the same thing now.

Have you seen this with lamps like in the article? That would be reason enough to not get them. It would only take one cap, but it would need to be a big one and they don't like heat! Also, it would screw up the power factor which is pretty good with the units as tested.

--

Rick C
Reply to
rickman
Loading thread data ...

Wouldn't this circuit have a terrible power factor? As the voltage approaches the higher values the current draw drops to nearly nothing. Since it is designed to work with 110 volts in running on 220 would be particularly egregious.

--

Rick C
Reply to
rickman

Any idea what PWM frequency these tailights use?

I have a Toyota that uses PWM for the panel light dimming. It runs at 400 Hz and I can't shake my head or hit potholes fast enough to see them flicker.

--
Paul Hovnanian     mailto:Paul@Hovnanian.com 
------------------------------------------------------------------ 
Porsche: If I went any faster, I'd have to eat airline food.
Reply to
Paul Hovnanian P.E.

How do you know it runs at 400 Hz? Just curious. Did you hook a photocell to an oscope or freq meter? I've thought the pulse rate should be around 1 kHz. I see this with taillights a lot. Mostly Caddies and a few imports. I think I've seen it on some Fords too. The Caddies with the tall taillights are the worst.

That reminds me of a thing I did in high school. I had an AM radio signal on the Oscope screen without sync. It would light up a larger or smaller area with the modulation. I taped a solar cell to the screen

signal. Just an aside.

--

Rick C
Reply to
rickman

I don't know, it's more than 100Hz I'd say, this may help...

formatting link

...but I'm surprised you can't see 400Hz. Guessing, you can sweep your eyes in 100ms which would give a line of 40 dots captured by the persistence of your retina.

Maybe you need to be further away, or maybe they have a capacitor in there so they don't actually flicker.

Cheers

--
Clive
Reply to
Clive Arthur

I hooked an oscilloscope to the panel light bus once.

-- Paul Hovnanian mailto: snipped-for-privacy@Hovnanian.com

------------------------------------------------------------------ In the land of the blind, the one-eyed man is lynched.

Reply to
Paul Hovnanian P.E.

It's the panel lighting. So there's only so far away I can get. About half the lighting is incandescent, so the lamp time constant takes care of that. The LEDs may just be located so that one can't sweep one's eyes across them that easily.

--
Paul Hovnanian     mailto:Paul@Hovnanian.com 
------------------------------------------------------------------ 
Your mouse has moved. Windows must be restarted for 
   the change to take effect. Reboot now? [OK]
Reply to
Paul Hovnanian P.E.

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.