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How do I convert an AC power source to a DC power source? Answered

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I have a small motor and a wall adapter for an answering machine. I need the wall adapter to work with the dc motor... any idea? A capacitor, maybe?

whenever I hook the wall adapter to the motor, it does a very predictable thing (vibrates uncontrollably..)

EDIT: I figured it out, with the help of the answers below
here is what i did...

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user
plumber_bob (author)2009-09-01

That would be a half wave rectifier, it's about as simple as it gets. Glad you got it working!

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Re-design (author)2009-09-01

To run a motor you only need to add a simple diode to the circuit. Changing the direction of the diode will change the direction of the motor.
Here's a good page to get some info
http://www.newworldencyclopedia.org/entry/Diode
You have to make sure that the diode you use is big enough to carry the current though.

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nepheron (author)Re-design2009-09-01

Thanks! I figured it out. I just hooked a diode to each end of the AC + and - wire. Works great now! I couldn't have done it without you guys !

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nepheron (author)Re-design2009-09-01
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nepheron (author)Re-design2009-09-01

Yes, I do have the correct diodes. Will I need 1 diode per - and + wire? I'm not very electrically educated.

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plumber_bob (author)2009-09-01

A full wave, or bridge rectifier is my suggestion. These can come in a ready to use package, or can be build out of 4 diodes. A simple search with google should bring up alot of info on bridge rectifiers, both packaged and discreet. A capacitor will filter out some 'noise', but it won't convert ac to dc. I'd post a schematic for you but my drawing skills,...well it wouldn't be pretty. :-) I hope this helps

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orksecurity (author)plumber_bob2009-09-01

A bridge rectifier will convert AC to pulsating DC. You would then want to filter the output to get something closer to constant DC -- that's where the capacitor comes in. As Bob said, websearch will find the info.

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nepheron (author)orksecurity2009-09-01

Thanks! I figured it out. I just hooked a diode to each end of the AC + and - wire. Works great now! I couldn't have done it without you guys !

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nepheron (author)plumber_bob2009-09-01

Thanks! I figured it out. I just hooked a diode to each end of the AC + and - wire. Works great now! I couldn't have done it without you guys !

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nepheron (author)plumber_bob2009-09-01

Thanks! I think I might have figured out a way. Cell phone chargers do that automatically so i might just go to Good Will and get a junk one.

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jtobako (author)2009-09-01

If you have a wall adapter that should give you DC power. Is the shaft on the motor spinning or just going back and forth quickly? If it's spinning, it may be out of balance. If it's vibrating back and forth, it may be a stepper motor, built to move a small amount at a time.

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Re-design (author)jtobako2009-09-01

Lots of wall adapters are a/c. He should check the label and see what his supply is.

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