[time-nuts] Hi Power LED Light power supply...

[Bob Camp]

Hi

A white LED is like a fluorescent bulb. The actual LED runs at UV and there
are phosphors in it to convert the UV to various colors of visible light.
The phosphor mix determines the color balance of the LED. It also adds
persistence to the output, just like a CRT. 

I do very much agree that you need a proper supply to run the LED's.
Rectified AC is *not* the way to go. 

Bob



-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Chris Albertson
Sent: Tuesday, September 18, 2012 12:42 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Hi Power LED Light power supply...

On Tue, Sep 18, 2012 at 5:21 AM, Bob Camp <lists at rtty.us> wrote:
> Hi
>
> I suspect those same 120Hz sensitive people would not be able to watch TV
or
> a movie :)....

In the old CRT type TV sets, the phosphor has some persistence.
Movies are modulated with a square waves, the frame blinks off and
goes dark then blinks on.   But the LED's brightness is fast enough to
track the sine wave and would be bright only for an instant with quick
pulses of light.

But just as bad as the flicker is that the LED is wasted and spends
most of the time being dim.

Power supplies are so easy to do that they are NOT the hard part.
With LEDS the hard part is the mechanical and optical design.  The
light must be indirect and defused and to do that correctly and
without much waste requires being creative and/or having some metal
working skills.

Chris Albertson
Redondo Beach, California

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