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Old 02-22-2010, 05:36 PM
bd525 bd525 is offline
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Default Small 120vac to 12vdc transformer

What is the smallest transformer (step down) that I can use to take 120VAC to 12VDC? I have project that needs 12vdc, but I am told as one of the requirements is not to use a standard wall wart transformer... Can I use a miniature PCB transmformer? Is there a better way to do this?

Thanks!
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Old 02-22-2010, 05:43 PM
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Bill_Marsden Bill_Marsden is offline
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How much current do you need?
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Old 02-22-2010, 08:33 PM
bd525 bd525 is offline
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about 50mA
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Old 02-23-2010, 08:42 AM
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t06afre t06afre is offline
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Is this a school project? Because perhaps then your teacher want you to build a simple power supply as part of the learning process. A simple power is made by a transformer,rectifier, filter cap, and linear regulator(s).
Also do not feel afraid to admit that it is a school project. You are welcome to ask your questions here in this forum
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Old 02-23-2010, 11:23 AM
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http://www.tamuracorp.com/clientuplo...cs/3FS-2XX.pdf about as small as I've been able to find in the past. Available from Digikey...$4. I've also gutted wall-warts for small transformers.

Ken
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Old 02-23-2010, 04:26 PM
bd525 bd525 is offline
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Hey Guys,
Thanks for all your replies!!

No this isnt a school project. I have been playing with electronics as a hobby and one of my personal projects caught wind of my boss and now had become part of a work project. I am learning as I do this so thats why I am asking questions here to get expert input.

I will check out the link here in a few.
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Old 02-23-2010, 04:44 PM
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Thanks for the KMoffet, that might work... also I am going to start hunting some wall warts to see what I can find...
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Old 02-23-2010, 07:01 PM
KMoffett KMoffett is offline
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If you are going to build this device for your employer, I would suggest you not go with cannibalized parts (wall-warts).

Ken
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Old 02-23-2010, 09:46 PM
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A cheap wall-wart AC-DC adapter has horrible voltage regulation. its output might be 12V with lots of ripple at its rated load current but might have an output voltage of 24VDC at a low current.
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Old 02-24-2010, 01:45 PM
bd525 bd525 is offline
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Thanks for the warnings guys, I will take your advice and only use the junk parts for my own testing...
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