View Single Post
  #4   Report Post  
Posted to sci.electronics.repair
[email protected] hrhofmann@att.net is offline
external usenet poster
 
Posts: 177
Default LED Series Christmas Lights

On Dec 27, 2:58*pm, Cydrome Leader wrote:
wrote:
I recently was given two strings of LED blue/white Christmas lights.
The bulbes are in series, with 35 lights in each string. *There are
also a couple of lumps in the series lines. *They appear to be just
resistors, not diodes, as I measure the same value (~500 ohms) with
either polarity of my multimeter. * My guess is that the resistors are
there just to decrease the current so that the LEDs are not running
overrrated. *I am thinking of putting/rewiring the two strings
directly in series and then reducing the series resistors until I get
the same overall brightness of the new 70-light string. *Has anyone
done any experimenting like this?


my guess is the string won't even light up with 70 LEDs in series. Messing
with that resistor will probably make the thing an even bigger fire hazard
than it is now. If you really want a long string of lights, just add an
extra wire the length of the first one to power the second and have the
use a common return line. Old zip lamp cord or speaker wire works nice for
stuff like this.


The separate sets have an outlet at the far end, so easy to put
together. My posting was just curiosity.

Back in 1944, when I was only 8 years old, my grandmother took me to
Macy's in New York City to buy me a Christmas present. She was
horrifed that the only present I wanted was a string of Christmas
lights so I could play with the bulbs and wires. First inkling I was
destined to become an electgrical engineer.

Fast forward to 1957, when I graduated from college with a EE degree
and got a job at Bell Laboratories. I had a dream job designing
switching system interconnect circuits, but also enjoyed playing with
Christmas lights.

Really fast forward to 2011, I still enjoy playing with Christmas
lights.