Need Negative Temp Coefficient Component for Xmas Lights Slow Turn-on

I have a couple of "sealed" devices that apparently have negative temp coef ficient devices inside of them that are placed between a power outlet and t he lights. The lights start out at 1/3 normal brightness and come up to fu ll level in 5-10 seconds. Soft turn-on means less light failures. I would like to have/make several of these, but I don't know what is inside the bo xes and don't really feel like tearing them apart if I don't have to.

Suggestions!

Reply to
hrhofmann
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Research Thermistors.

John :-#)#

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Reply to
John Robertson

I was being lazy, had hoped for some part numbers .

Reply to
hrhofmann

They call them "NTC Thermistors".

Look at Mouser, you need to estatemate the wattage your light string uses so you can properly select the correct one that will create the voltage drop you need when cold and reduce down to it's minimum value when hot.

Reply to
Maynard A. Philbrook Jr.

efficient devices inside of them that are placed between a power outlet and the lights. The lights start out at 1/3 normal brightness and come up to full level in 5-10 seconds. Soft turn-on means less light failures. I wou ld like to have/make several of these, but I don't know what is inside the boxes and don't really feel like tearing them apart if I don't have to.

** The devices are probably "NTC thermistors".

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They come in a range of sizes and resistance values.

You need to measure the cold resistance value to establish the latter.

Last time I needed some, I found them on Ebay from dealers in HK.

... Phil

Reply to
Phil Allison

Thanks for the info, I'll measure the cold resistance tomorrow, right now the lights are all on.

Reply to
hrhofmann

Is this what you want?

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If you Google "inrush currebnnt limiter", you can also buy the key component form Digikey or Mouser for less than $5.

Reply to
jfeng

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