Converting 9VAC to DC

Thread Starter

summersab

Joined Apr 8, 2010
161
First off, I'm a mechanical engineering graduate. It's been literally years since I've had an electrical class. Feel free to treat me like a bumbling moron.

Second, I'm sure this issue has been covered before, but I can't find anything SPECIFIC. Perhaps I'm not using the right search terms . . .

I'm modifying an alarm clock of mine. It is powered by a standard wall-wart type power supply with an input of 120VAC and an output of 9VAC @ 900mA. So far, I have been incorrectly assuming that the output was 9VDC - I've simply never seen a wall-wart that goes from AC-AC. My project requires 5VDC (though higher is fine - I already have circuitry in place to handle higher/unstable DC inputs using a Zener diode), and amps can be fairly low. How do I convert 9VAC to DC?

Thanks!
 

SgtWookie

Joined Jul 17, 2007
22,230
Zener diodes won't provide decent regulation unless the current through them is fairly constant.

If your circuits' current draw is low, and you take a 9v@900mA AC wall wart, you might be unpleasantly surprised at how much voltage you'll get out of it.

Post your schematic as it exists now to establish a baseline, and so that we can get an idea of your power requirements.
 

ifixit

Joined Nov 20, 2008
652
The 276-1152 should work, however, there is no data sheet to use to verify if temperature derating is required. I'm going to guess it would be okay at room temperature and soldered to a PCB.
 
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