Instructables

Is there a simple way to be able to run low voltage things like LED arrays from the mains power?

Basically I want to be able to make some LED lights to light up my workbench in my shed and it'd be easier if I could just plug them into the wall instead of having to replace batteries every now and again.

pandyaketan3 years ago
I have made many LED projects on AC Mains... They are very simple, but after much research...Hope they help.

reg
ketan
just use a transformer. you get ones that plug straight in to the wall that go as low as 1 or 2 volts
seandogue5 years ago
For the USA, !N4002 diode in series with LED in series with a (nominally) 33K resistor yields about 5mA. Diode block the negative going part of the sine wave, 33K is voltage-dropping/current-limiting to prevent the LED from seeing excessive voltage. a 1N4003 or 4004 would be necc in countries where the mains are ~220VAC and the resistor would have to be upped in value as well.
umm- "wall wart" a step down transformer was designed for this because leds only consume 1.6 volt so the rest of the mains voltage would need to restrained by a resistor that would be in an un-real price range for a resistor rated at 400Watts or more also it probably be bigger than a desk and emmit allot of heat. this is why we step down the voltage first then construct a circuit with LED and current limmiting resistor.
The best way uses 1 common capacitor and 1 common resistor plus the power cord and the LEDs.

The schematic and description are Step 2 in my instructable. I know it sounds like it can't work but it does.

http://www.instructables.com/id/AC-Powered-White-LED-Circular-Magnifier-Work-Lamp/

jacob29105 years ago
you can buy a down converting battery pack we use them at school they can go down the 3v and up to 24v
pyroten5 years ago
You could go buy a step down transformer from most electronic stores from 240vac to something like 5 or 12v. Then if needed you could look for a AC/DC converter or make one yourself. *i'm sure there'll be some on instructables*. From the 12v you could either wire it in series parallel or just go straight resistors.
ewalk5 years ago
If you are like me, you probably have a bunch of old power adapters laying around, from old cell phones, routers, laptops... Just cut the tip of the connector off and you have a 5v DC(or whatever the adapter is for) ready to plug your LED's into. To be safe and for ease of use, I connect a 4 pin computer power plug to the adapter, then build my circuit with the opposite of the one on the adapter. That way it is safer(not hard wired to the adapter) and it is interchangeable. It is really simple to do. Let me know if you want an instructable for it.
Skip (author)  ewalk5 years ago
An instructable would be a benifit to both me and the community
ewalk Skip5 years ago
Awesome!! THis will be my first. I will post here with a link when I am done
Skip (author)  ewalk5 years ago
thanks
lemonie5 years ago
Why not just use a low-energy (mains) bulb? L
because this is instructables, and its WAY more fun - and the same cost or less - than to use prefab ones.
Skip (author)  frollard5 years ago
The speaker of truth speaks wisely!
Is none of the AC-powered LED projects on Instructables suitable? Like this one?
Skip (author)  NobodyInParticular5 years ago
This is pretty much the answer I was looking for. I didn't know what to search for.
keydogstony5 years ago
Any 9v or 12 V dc ac adaptor will work.