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

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

Original poster: "Peter Terren" <pterren1-at-iinet-dot-net.au> 

I have used my Luxeon Star 180,000 mCd white LED to do this and to check
sync with my SRSG. You want the LED to fire only at the peak of the sine
wave (1/2 or full wave rectified) which might be 9 - 12 V depending on the
transformer. It helps to have a zener diode eg 6V in series, and to run
everything from a variac and you still need the current limiting resistor.
It easily handles the 50 Hz and will go much higher.
See
http://tesladownunder.iinet-dot-net.au/electronics.htm#High%20power%20white%20LE
D
Cheers
Peter (Tesla Downunder)

 > Original poster: "Daniel Kline" <daniel_kline-at-med.unc.edu>
 > An engineering friend says a high-brightness LED on a
 > low-voltage transformer, like 6 Volts, connected through
 > a suitable resistance, should flash at 60Hz in sync with
 > the 60Hz mains. (50Hz for you all over there :)
 > It seems too easy to me...he thinks that the LED may have
 > a "persistence" issue. In other words, just because it
 > turns off quickly doesn't mean it stops emitting quickly.
 > Comments?
 > Thanks,
 > Dan K