110v to 3v???

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

BigPatBrewer

Well-Known Member
Joined
May 23, 2011
Messages
71
Reaction score
0
Location
Tucson
Is there a way to go from 110v to power an LED that is rated to 3v? Can I use a resistor? Bear with me, I am still trying to figure out all this electricity stuff. I could seem to find what i was looking for in my searches so far. Thanks in advance!

EDIT: I just found out the LED is rated to 12v
 
Pretty sure you want 3V DC power for that LED, not 3V AC. So what you could do is use 110V to power an AC to DC wall wart that outputs 3V (or you could use a resistor to alter the DC Voltage of a wall wort with a higher voltage).
 
BTW, might be easier to just use a lamp rated for 110VAC if you don't already have a DC power supply in your system (and have no other uses for one other than the LED).
 
The switch I am using, lights up with a LED. The switch is rated to 120v but for some reason, the seller told me the LED is 3V only. I was trying to avoid using a adapter that you plug into the wall if possible
 
A light up switch should be ok if it is rated for 120v idk what that 3v business is. Its the light inside the switch to say its on right?

If you must use a 3v source go to a second hand junk store.. they normally have boxes of wall warts. Better than buying brand new.
 
No, you put the led between the 1k ohm resistor and the capacitor. One thing to know about all diodes, including LEDs is that they only pass current one direction- great for dc, but ac presents a problem and will fry them. You may also need a reverse path diode since you are using ac, not dc. But that depends if your led is multidirectional ( by which I mean if your switch or whatever you have is a combination of opposite direction LEDs or just a single led that passes current only one direction.). I have some switches that are blue and green that employ using two leds of opposite direction. They only needed the capacitor and resistor to be installed. I HAD some white led switches that only had a single led in them, they got fried because i needed an auxiliary diode to allow the reverse ac a safe path, but the blue and green switches had two LEDs in reverse direction, so didn't need the correcting diode. Good luck. I'll try to get a picture....
 
Just as a recommendation, you might want to pick up some LEDs to do your "testing" with.

I imagine a switch with integrated LED is not cheap and you don't want to let the magic smoke out of it.
 
Is it this switch?

1


ledswitch.JPG
 
I cannot see the link but it sounds like you may have a 12VDC rated switch. It should be printed on the switch somewhere. If so, it is not rated for 120VAC and probably not a good idea to use it.
 
I cannot see the link but it sounds like you may have a 12VDC rated switch. It should be printed on the switch somewhere. If so, it is not rated for 120VAC and probably not a good idea to use it.

TO view the link just click on it, after it fails to load, highlight and delete everything before this:
1
http://www.ebay.com/itm/220807727775?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649 then reload with the new link. Unfortunately we have to view links this way until HBT admins fix the fyurl bug.

So the "clicker" must take this data out of the link:
http://www.fyurl.com/rr.php?site=www.homebrewtalk.com&url=

It says it's rated for 10A 120VAC but then just says 12V LED. It seems really inconvenient unless to use this switch unless you already have a 12VDC power source in your panel. For a couple dollars more, Auber sells a good pushbutton switch that you can just use 120VAC or even 240VAC to light the LED.

If you're stuck with these buttons you'll have to use a 12VDC power supply. The cheapest way is to use a "wall wart" but they're also bulky and not intended to be mounted in a panel. Another way would be to purchase a 12vdc power supply. Here's one from Amazon:
http://www.amazon.com/dp/B00525652K/?tag=skimlinks_replacement-20
 
Last edited by a moderator:
The one from Amazon is only one amp, so you could probably power a few pushbutton switches with it. Hard to say how many exactly because the ebay seller doesn't give any details on the LED.
 
I guess this is what I get for trying to do this on the cheap. The Auber switches are nice but they are also about $10 more a switch. I was hoping I could put something inline to drop it from 110vac to 12vdc but I guess I will just have to use a wall setup. Thanks
 
Back
Top