Thread: Quick Question about Modifying my Adapter

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I just found an AC to DC adapter (12V DC out). I want to cut off the end to hook up to my pre-wired LEDs for pin-spot lighting.

There's a little cylinder thing near the end of the cord that you would plug in to the accessory (NOT the wall). What is that little cylinder? Do I need to keep it on when I cut off the end? Does this make sense? If not, I can post a picture later.

That "little cylinder" is the jack that normally would plug into whatever the wallwart originally powered. If you are planning to hook the power supply directly to your LEDs, you would not need to save the jack, but you WILL need to know the polarity of the wiring. On the wallwart itself should be a pictoral diagram that would indicate whether the outside or inside of the jack is the positive (+) or negative (-) wire. You can also check the polarity with an ohmmeter (VOM) if you have one.

Like Runfromron said you don't need the end piece. I don't believe it will hurt your lights if you get the wires backwards...it just won't light so you switch the wires if that happens. Most of the time the wire with a white line or white dashes running down it is the positive.

Also, look to see if the adapter says 'regulated' on it. If it doesn't, you'll need to make sure your lights pull close to the amperage it's rated for or it will put out more than 12V and burn out your lights faster.

And wiring the lights backwards won't hurt them. I've done it often enough.

Thank you for the quick responses... I guess I may not have been clear, though. The part I'm referring to is circled in red in the picture.



Does that make more sense? Anyone know what it is?

the little cylindar i think is a ferrite core, used to block interference and sutch if memory serves . it will work without it but i would probably leave it

That's kind of rare for there to be a ferrite core on a power block. Usually it's used on things like computer cables. Was the power block originally for speakers or an amp? Power modulation on those things can introduce interference in the sound so it would make sense for there to be some kind of filter on it. But yeah, leave it on, it won't hurt a thing.

Well, sounds good! Thanks for the advice... I'll leave it on just to be sure! This is why I love this forum - smart people with a love for all things Halloween!

I don't bother to cut off the ends of these wall warts...I just use one of these:

https://www.adafruit.com/products/368

Never seen those before. Thanks JeffHaus. Do they come available in other jack sizes? I have a fine collection of wall warts for projects, but each one seems to have a unique jack size.