How To Tell If LED Is Isolated From Sink?

I'm modding a light using a LUX 3 (bare emitter) and a Downboy. I glued the LED to the heat sink using Artic Alumina Adhesive. I think it is isolated from the Downboy, but I'd like to test it to be sure.

A brief test with the Ohm-Meter, prior to mounting, indicates that there is no continuity between the LED inputs and it's slug. So, how do you test it?

IIRC, a white Lux emitter is isolated; it was the red/amber ones that you need to be careful with.

It's pretty confusing trying to determine the proper way to wire a Downboy. Lot's of people say it doesn't matter if the grounds are common.

This if from a "how to" on Wayne's site:

"It is a good idea to apply a layer of nail polish to the bottom of the emitter slug. This will ensure that the slug is isolated from the module. This is crucial for the use with the DownBoy and Wizard converters."

I really don't want to discuss wether it's needed or not. Just want to know how to test to see if it's isolated.

Anyone know?

One of our very-talented EEs made a post within the last few months of how to measure isolation with a DMM. It took into account the ESD (ElectroStatic Discharge) protection dioded on the different flavors of Luxeons. I wish to heck I had bookmarked it! (I'm also too lazy tonight to try and hunt it down. I think it was in the Electronics/Batts board.)

Larry

Thanks, I found it. "Isolation of Luxeon slugs" is the title and evan9162 is the author. Good info.

yup thats the one!