running a 240VAC led from 24VDC

[Jared]

Hi guys,
I have a small project I am working on. I have a 240V led circuit which I need to run off 24V. At the moment the LED does light but very dim.
I am looking into putting some sort of device before the LED. The LED type is unknown as it is meant to run of 240VAC.
As the current is very very low to run the LED so I am thinking of some sort of capictor, which can charge and discharge the 240V multiple times a sec.
Any advice would be great,
Thank you Jared

 

[KrisBlueNZ]

Hi Jared and welcome to Electronics Point.

You can reduce the values of the resistors on the LED board to make it run from a lower voltage.

At present the three on the underside are all 100 kilohm (marked "1003"). I can't make out the marking of the one on the other side.

Adding a 12k resistor in parallel with each of those resistors should do the trick. You can do this by placing the 12k resistor on top of the existing resistor and soldering it "across" the existing resistor, one end at a time. Alternatively you can remove the existing resistors and replace them with 10k resistors.

It's possible that not all of the resistors need to have their values changed. If you can show us pictures of both sides of the board where the copper tracks are clearly visible and traceable, we may be able to tell.

When you've modified the board, I suggest you mark it as "modified for 24V" (either directly with an indelible pen, or using an adhesive label).

 

[Jared]

Thanks Kris,
Originally I shorted out the resistors and yes, it is brighter but not as bright as 240V. What I would ideally like to acheive is a simple circuit placed onto the 240V tails as we do not have to open each unit and resolder.

This is a 240V bell press mech switch, with a LED, which is being used for Leviton Home automation. The automation system runs off a 24V bus.

I am thinking along the lines of a 24V - 240VAC inverter circuit which will require hardly any current as it is only to light the LED.

Cheers,