×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Rectifying Triac Output

Rectifying Triac Output

Rectifying Triac Output

(OP)
Hi All,

I've been looking for a circuit design that can rectify the output of a typical household dimmer switch into nice clean 12v DC. The reason I'd like to do this is that I have a light fixture with an incandescent bulb that is perfectly happy to dim with the triac, but I want to run some 12v electronics off the same wire. I took a stab at this but it seems pretty hairy, maybe it just shouldn't be done? I imagine that a dimmable LED bulb contains driver circuitry something like this? Any thoughts would be much appreciated.

RE: Rectifying Triac Output

A wall-wart is better and safer. Remember that a dimmer usually does't isolate from the grid, so you can easily kill yourself or start a fire.

Your assumption that it shouldnt be done is absolutely right.

There are other issues also - like difficulty to smooth that extremely pulsating voltage. And also avoiding overvoltage that will kill your load when there is interference o the line.

Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

RE: Rectifying Triac Output

There's a reason that dimmable LED and CFL lights are expensive. There's a bit of circuitry involved in getting everything to work right; it's definitely not something for a DIY project.

TTFN
FAQ731-376: Eng-Tips.com Forum Policies

RE: Rectifying Triac Output

Reading between the lines... You probably need to rewire the room so that you can run a normal 12Vdc output power supply from a normal AC outlet with the normal AC waveform.

If you still need a light dimmer, connect it only to the light fixture.

RE: Rectifying Triac Output

(OP)
Thanks for the advice everyone, I'll do a bit of a re-think.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources