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olingerjccj
06-05-2010, 11:24 AM
Ok easy enough to cut it down to 50, but can you cut it down to 4 sections of 25?

Thanks
John

gizmo
06-05-2010, 11:47 AM
easy answer is NO

technical answer YES but you will need to add a resistor to "eat" up the extra voltage..then you will need to worry about heat from the resistor. You can substitute a house light bulb (of the correct wattage) for the resistor but if it burns out you will loose burn out (blow) the entire string PDQ.

I have several projects im thinking about that only need 10-20 bulb strings and brought up this subject last year and got the above answers (not what i wanted to hear).

The option im thinking about is making custom LED strings and running them on a DC power supply. Lots of info floating around on how to do it.

hope this helps
scott

sjwilson122
06-05-2010, 11:48 AM
Technically yes, they can be cut to whatever size you need. The problem is the bulbs. Assuming you are using 120v supply, for a 25 light string you would need 4.8v-5v bulbs to give a similar look as the "standard" strings. You could use lower voltage bulbs and a ballast resistor but the resistor is going to get pretty warm.


Gizmo beat me by seconds.......

dmcole
06-05-2010, 01:19 PM
There is such an animal as a 20-count mini-light string -- it uses six-volt bulbs. A little Googling around indicates that they are only available in clear and multis; there are no single-color strings. One guy suggests that you can buy five of the multi-colored, 20-count strings and pool all the bulbs together and then make strings of red, green, blue, yellow and pink.

HTH.

\dmc

Dennis Cherry
06-05-2010, 01:40 PM
Also Google 12 volt mini bulbs.

Just gave a case of them away last year.

ErnieHorning
06-05-2010, 03:22 PM
If you go LED, you can pretty much do anything you want.

With incandescents, when one burns out, the rest will get it's voltage added to them. The fewer that you start out with, the faster they all will burn out after just one does.

dirknerkle
06-05-2010, 06:04 PM
You could use a transformer to cut the 120vac down to a manageable value for 25-light strings. It shouldn't be too hard to find one that will take the voltage down to 30 VAC. 25 mini-lights would require about .0825A.

Mathematically, it might even run through cat5 to a 4-channel SSR and AC power and control signal could conceivably coexist on the same cable, although I'm not sure how noisy the line might be and it could possibly cause misfires...

But your best bet would probably be to go with LEDs.

olingerjccj
06-05-2010, 06:48 PM
...

But your best bet would probably be to go with LEDs.[/QUOTE]

LOL not this year, so I will just use 50 ct and let it go at that. I was just trying to take off some weight off my firework leads and a spacing issue.

John

ErnieHorning
06-05-2010, 08:04 PM
One other option, a single 1N4004 diode in series should give the equivalent 54 volts of rectified AC. This should allow you to use 22 mini lights for full brightness, 25 would be just slightly dimmer. This way, if a bulb burns out, the shunt should still function correctly.

Virtus
06-05-2010, 08:09 PM
One other option, a single 1N4004 diode in series should give the equivalent 54 volts of rectified AC. This should allow you to use 22 mini lights for full brightness, 25 would be just slightly dimmer. This way, if a bulb burns out, the shunt should still function correctly.

This may be just what I was needing in a pretty complicated, multichannel, coroplast item I have under construction. I have a couple places where 50 is just too many. Thanks for the tip!

gizmo
06-05-2010, 10:04 PM
One other option, a single 1N4004 diode in series should give the equivalent 54 volts of rectified AC. This should allow you to use 22 mini lights for full brightness, 25 would be just slightly dimmer. This way, if a bulb burns out, the shunt should still function correctly.

Can you explain this more???

is a 1N4404 a part # or a type of diode?

are you talikng about regular AC minis? asking because i dont get the rectified AC part

in series?? just solder the diode in hot leg (or does it matter) and in what direction?

this may be the answer to my candy cane project

alanp
06-05-2010, 11:03 PM
I've used the diode trick all last year, it works great.

To answer your questions it doesn't matter if you put it on the hot leg or the netral leg as long as it's in series with the lights.

What the diode does is to only let half the cycle (half the voltage also) go thru.

The 1n4004 is a industry standard number just go to Mousers and type it in.

One last note, you can still dim the mini's with no problem.

olingerjccj
06-05-2010, 11:22 PM
I just want to be sure I know this is so basic but like this

gizmo
06-05-2010, 11:34 PM
I just want to be sure I know this is so basic but like this

Im not sure but to me series would mean you cut one wire ( hot or neutral) and put the diode inbetween you cut.

still need to know if the direction of the diode matters?

thanks scott

StandingInAwe85
06-05-2010, 11:36 PM
Does anyone know if this gives the "strobing" effect like the half-wave LED's do? I think due to the nature of incandescents it wouldn't be noticeable, but having someone that can confirm it would be helpful before everyone starts chopping up their lights.

dirknerkle
06-05-2010, 11:38 PM
Yes, this would create the "half-wave" strobe - the diode is cutting the full wave pattern in half.

StandingInAwe85
06-05-2010, 11:39 PM
Im not sure but to me series would mean you cut one wire ( hot or neutral) and put the diode inbetween you cut.

still need to know if the direction of the diode matters?

thanks scott

That's correct, you would cut one wire and put it in between. In this case, I don't believe the direction would matter.

gizmo
06-06-2010, 12:13 AM
That's correct, you would cut one wire and put it in between. In this case, I don't believe the direction would matter.

didnot think it would its just cutting off one side of the sine curve

thanks for the info

ErnieHorning
06-06-2010, 12:41 AM
didnot think it would its just cutting off one side of the sine curveIt`s sort of like PWM, at 50%. The time on and the time off being the same will give you half brightness.

Most incandescent lights won't flicker very much with 60Hz halfwave. You really have look at it hard to see it; they're much slower than LED's.