i am struggling to find a 9v AC wall wart
is there a simple way to get dc to ac ?
or how do i reduce 12v ac to 9v ac ?
Why do you need to get AC from DC? If you want, you can use arduino and transistor and simple blink code.
Gadget999:
i am struggling to find a 9v AC wall wartis there a simple way to get dc to ac ?
or how do i reduce 12v ac to 9v ac ?
Why don't you tell us what you're trying to achieve, not what you're doing?
And what does this have to do with Arduino?
is there a simple way to get dc to ac
No.
Now depending on what you want to do there are several complex ways, the more like real mains AC you want the more complex it gets.
or how do i reduce 12v ac to 9v ac ?
Using a transformer with a 3:4 turns ratio.
just to confirm - this is not a arduino related problem
i have a 12v ac wall wart
i have 12v ac - need 9v ac
As I said:-
Using a transformer with a 3:4 turns ratio.
You might have to wind it yourself of get it wound for you. What current are we talking about?
I can't help but think it would be cheaper to make or buy one of the right voltage.
Is it that critical that it is 9V AC, most AC loads are not that fussed as to the exact voltage because while it is 9V RMS it will be 12.7V peak.
his is not a arduino related problem
Fine it is in the right section.
What is the goal? Why do you need 9 volts AC, plus or minus how much?
I bought some 9VAC CUI wall warts from Digikey.
Again, I ask (curious) why do you need 9 volt AC, rather than DC ?
Gadget999:
just to confirm - this is not a arduino related problemi have a 12v ac wall wart
i have 12v ac - need 9v ac
Gathered that from original post.
WHY do you need 9V ac (is what we're all wondering).
....and please don't respond with, "to power my project". 
We want to know what sort of project needs 9v ac?
Thank you!
the 9 v AC is for an audio mixer
i guess ac is less noisy than dc converted from ac
most professional audio equipment is low voltage AC
the current requirement is 500 ma
Thanks for the new info.
i guess ac is less noisy than dc converted from ac
Well, I would not agree with that, but.
I suspect that circuit just takes the 9 volt ac, and runs it through a diode or two to convert it to dc.
I don't think you need to turn dc to ac to get 9 volts dc again. Just try supplying the 9 volts dc, to the plug labeled 9 volts ac.
I don't think you need to turn dc to ac to get 9 volts dc again. Just try supplying the 9 volts dc, to the plug labeled 9 volts ac.
Well it could be that the audio equipment needs a split rail so it will require AC to generate that.
There are going to be voltage regulators inside the equipment to run the electronics so you have to consider what an over voltage would do for that.
There are two things to consider, one is the voltage itself exceeding the voltage of the pre regulation capacitors and the second is the extra voltage the regulators will have to drop generating more heat.
I don't think the jump from 9V to 12V will be that significant and you will probbly get away with it but those are the points I would consider.
Huh uh.
Audio mixers often use AC because they need to resolve positive and negative voltage with respect to the audio reference / ground. Most op-amps for example are designed to run on split rails. They CAN be run from plain single-rail DC if there's a bias voltage bus to serve as a Vcc/2 reference. But that's a design decision, and can't be assumed to exist.
In general, plugging DC power into an AC inlet is not wise, without at least examining the topology first. There's even a possibility you'll find a transformer in there to provide alternate rail voltages, or just for isolation. (Although typically the latter is achieved via the low-voltage AC source itself. Still, if you did find such a thing, plugging in a DC supply would saturate the core, and then things get exciting.)
Well, lots of guessing going on here. I guess you know what 9 volts rms, is peak to peak? How about a URL for this device, so we can get the real specs?