How to convert 12VAC to 12VDC?

[CZroe]

Probably have some 12v automotive rectifiers just lying around from all my motorcycle parts. It looks like a little slab with fins formed on it to dissipate heat.

 

[MrTeal]

Keep in mind that your LED lights are probably essentially a free half wave rectifier.

That's how many LED Christmas lights and the like work, they are a string of diodes (with a current limiting resistor) that conduct electricity during the positive half of the waveform and are off during the negative. The LED lights will be probably considerably dimmer than if run straight off 12VDC, and you'll get the flickering that some people notice with cheap LED Christmas lights, but that might be a cheap solution if you can deal with it.

 

[Red Squirrel]

Keep in mind that your LED lights are probably essentially a free half wave rectifier.

That's how many LED Christmas lights and the like work, they are a string of diodes (with a current limiting resistor) that conduct electricity during the positive half of the waveform and are off during the negative. The LED lights will be probably considerably dimmer than if run straight off 12VDC, and you'll get the flickering that some people notice with cheap LED Christmas lights, but that might be a cheap solution if you can deal with it.

Yep that's how typical LED Christmas lights are, that's why you can see them flicker at 60hz. Bridge rectifier makes them flicker at 120hz while increasing duty cycle by inversing the negative wave to positive.

 

[piasabird]

When it says general hardware, they mean computer hardware. This is not a forum for electrical engineering. There is another forum called "Highly Technical" for subjects like this.

You have to control the amps or you might kill someone.

 

[CZroe]

When it says general hardware, they mean computer hardware. This is not a forum for electrical engineering. There is another forum called "Highly Technical" for subjects like this.

You have to control the amps or you might kill someone.

Pretty sure it got moved here from OT.

 

[Red Squirrel]

When it says general hardware, they mean computer hardware. This is not a forum for electrical engineering. There is another forum called "Highly Technical" for subjects like this.

You have to control the amps or you might kill someone.

I'm not sure if 4 diodes in a bridge configuration would qualify as highly technical either. 😛

Seriously OP, just use a bridge rectifier and call it a day. You can make them or buy them premade. You're not dealing with much voltage or current so pretty much anything will do.

One of these would more than work fine:

http://www.digikey.ca/product-detail/en/GBJ1502-F/GBJ1502-FDI-ND/775735
http://www.digikey.ca/product-detail/en/GBPC1502-E4/51/GBPC1502-E4/51-ND/2139811
Or if 15 amps is not enough:
http://www.digikey.ca/product-detail/en/MP506-BP/MP506-BPMS-ND/1130339

Totally overkill mind you but I always like to over engineer things especially when we're talking a couple dollar worth of parts. But in your case if you can find an old circuit board or something just rip 4 diodes off and make one will work too but by buying premade at least you know the ratings.

 

[mfenn]

When it says general hardware, they mean computer hardware. This is not a forum for electrical engineering. There is another forum called "Highly Technical" for subjects like this.

You have to control the amps or you might kill someone.

We get these sort of threads here from time to time. They're worthwhile even if they aren't in the majority. There's been useful discussion as proof of that.

mfenn
General Hardware Moderator

 

[Stubby01]

Howdy, first time posting. I found this thread through searching online. We have a LED landscape lighting system 120VAC to 12VDC and I am getting tired of spending $25 per unit just to replace the LED portion of the assembly. I would like to see if I could build a replacement LED board myself? The system has been installed coming up on 4 years and now lights are failing. I wish the manufacture would produce a replacement LED assembly kit.

 

[corkyg]

Your question is totally out of place. This Forum is for computer hardware only. Your query might better fit in the Home and Garden Forum.