24 Feb
2010
24 Feb
'10
5:33 a.m.
On Feb 23, 2010, at 8:33 PM, Chuck Guzis wrote:
According to
http://www.muanalysis.com/publications/Quantum-Wells-in-Seasonal-
Department-Christmas-Lights-LED.pdf
the 70-LED strings get by with a resistor only. The 100 LED strings
appear to use a diode. Heaven forfend that a diode bridge be used
for them--that could cost additional cents per string.
There's some fellow on the web who's been making various line/mains-
operated lights using only a resistor in series with a single LED.
Weird--I would have at least paralleled the LED with another
resistor. I'll try to find his web page, if anyone's interested.
There was an article many years ago, in CCI I think, about running
PIC microcontrollers from line voltage through a very large
resistor. Scary stuff.
-Dave
--
Dave McGuire
Port Charlotte, FL
However, to my eye, the biggest abomination are cheap
Christmas tree
LED lights with very pronouced flicker. I haven't researched it,
but I suspect that the LEDs in such strings are hooked in series and
used to self-rectify the line current.
I would hope not. The maximum revers voltage for most LEDs is quite
low.