RE: LED at 60 HZ? (was RE: Radio Shack Strobes)

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Terry Fritz <teslalist-at-twfpowerelectronics-dot-com>

Hi,

The LED's pulse width is fairly long compared to the xenon light.  Thus the 
image will be a bit fuzzy.  The LED's resistance is too great to drain the 
firing cap instantly.

Cheers,

         Terry

At 06:55 AM 3/2/2004, you wrote:
>Hi Terry, Dave
>
>As an experiment, I built this simple LED strobe to compare it to my xenon
>flash tube based strobe which I have already built.  The xenon strobe is
>built around a UJT based zero-crossing detector, an SCR and a trigger
>transformer.
>
>The reason I did the comparison is because of the inherent problems with
>xenon flash based strobes - i.e. short run times, about 10 seconds max.,
>before things start overheating and the strobe starts to flicker.  Both the
>tube, and the series load resistor on the xenon positive output gets very
>hot very quickly.
>
>The LED strobe works reasonably well, but there is some smearing of the
>image of the SRSG platter - about an inch or so at the platter electrodes in
>my case.  The xenon strobe leaves the platter image rock steady stationary.
>
>Is the smearing really caused by LED persistence, or is it something to do
>with the type of LED I was using (a water-clear ultra-bright 5mm red LED)?
>
>Regards
>Ian
>
> > -----Original Message-----
> > From: Tesla list [mailto:tesla-at-pupman-dot-com]
> > Sent: Monday, 1 March 2004 2:13 pm
> > To: tesla-at-pupman-dot-com
> > Subject: RE: LED at 60 HZ? (was RE: Radio Shack Strobes)
> >
> >
> > Original poster: "Dave Kyle" <dave-at-kyleusa-dot-com>
> >
> > Hi Terry,
> >
> > I had been looking for a way to easily check my SRSG timing
> > so I built your
> > LED strobe and it works great! Thanks for posting the schematic.
> >
> > Dave
> >
> > Terry LED Strobe
> > http://home.socal.rr-dot-com/dkyle/images/Strobe.jpg
> >
> > Inside
> > http://home.socal.rr-dot-com/dkyle/images/Strobe_inside.jpg
> >
> >
> > =========================================
> > Dave Kyle
> > Austin, TX USA
> > Email: dave-at-kyleusa-dot-com
> >
> >
> > -----Original Message-----
> > From: Tesla list [mailto:tesla-at-pupman-dot-com]
> > Sent: Tuesday, February 24, 2004 5:49 PM
> > To: tesla-at-pupman-dot-com
> > Subject: Re: LED at 60 HZ? (was RE: Radio Shack Strobes)
> >
> > Original poster: Terry Fritz <teslalist-at-twfpowerelectronics-dot-com>
> >
> > Hi,
> >
> > You can't use just straight AC since the sine wave voltage
> > will spear the
> > image.  You need very fast bright "short pulses" to freeze an object's
> > motion.  Here is a simple circuit for an LED strobe that works ok.
> >
> > http://hot-streamer-dot-com/TeslaCoils/Misc/STROBE.ZIP
> >
> >
> > Cheers,
> >
> >           Terry
> >
> >