Ok.. so I have screwed up (Wall Wart help)

[littleyoda99]

So... as some may know I recently finished a 1/350 Enterprise... but as I discovered after I had the model sealed up, and past the point of no return... I had used an AC-AC wall wart instead of an AC-DC wall wart...

let the flames begin.

Anyhoo, I am having a hella time finding a replacement. My development wall wart burned out, it was a 12VAC 1.25A .... and I thought I could get buy with a 1.0A 12VAC... buuuut it burned out on me too.

So I am wondering what my options are. I am wanting one that is 1.5A 12VAC because I believe that is the Amps I need to keep it from burning out, and obviously I don't want to go for one of the 2.0A+ ones because I think they would give me too much and cause bigger problems that I will not be able to fix.

Anyone have any tips to help me out of this mess?

Ironically, I have about 6 wall warts at home... all 9-12VDC... the one I grabbed for this model just happened to be the only AC one I had.... doh.

[DLMatthys]

I had used an AC-AC wall wart instead of an AC-DC wall wart...

let the flames begin.

Donno...Consider it a life lesson, endeavor to read labels from now on.

[Disillusionist]

Don't worry about using a supply that's rated at 2 amps or higher. That's simply a maximum rating. It won't "push" more current into your circuit. It'll just run a little cooler if the model doesn't require that much current.

[Sparky]

yes you can always use a larger than needed power supply,

To those who think its a good way to 'protect' the circuit in the model, you should not be using the power supply's max output rating as a limiter for your circuit. The power supply will be running at max load and tend to burnout and or surge its power delivered [as the burnout occurs] which will cause damage rather than protecting your circuit.

You can add a fuse in line if you want, say to use a 5 amp power supply on something that should not draw more than 1.25 Amp. 1 n' quarter fuses like this are pretty common you should be able to find them at electronics stores (maybe even radio shack). I know we sold plenty of them when I worked at Sparky's Electronics in Fresno, and you couldn't find anything that remotely could be called specialized electronics in Fresno.

You might consider a reverse protection diode too. Though they get pretty big and rather expensive for the higher current versions. Also you loose 0.7 volts through them, this resistance creates heat so don't put it in the model, rather the base and have plenty of heat dissipation space for it. Keeps you from running power the wrong way through the system.

[Pat Amaral]

Keep in mind that using an unregulated power supply at less than its rated
current will likely cause it to supply a higher than rated voltage. This can
also cause problems. I've measured unregulated 12 volt wall warts, rated for
say, 500mA, reading 16 to 18 volts when running at 100 or 200mA. If at all
possible, make sure the power supply is regulated. If it's not, it's a good idea
to use a regulator in the power distribution to the circuit (after the output of
the wall wart but before the lighting circuit itself). Regulators can get warm
so you need to account for that as well.

[littleyoda99]

I had used an AC-AC wall wart instead of an AC-DC wall wart...

let the flames begin.

Donno...Consider it a life lesson, endeavor to read labels from now on.

bah reading is overrated !




Thanks for the info guys... very helpful!