Any body know what LEDs &/or resistors to buy to give me the equivalent light output to a 21w Bulb? They are to be run on a 12v circuit.

 

are you using them in the house or a car & what for .

 

In a car. Tail lights to be precise.

 

Don't want to sound like a smart arse but, you can buy them in allmost every carshop. Why do you want to know?

 

I don't want replacement led bulbs. I'm making custom rear lights and need to source individual led's!

Having scoured the internet it seems a standard incandescent 21 bulb is 180-200 lumens, the problem I'm having is led's are measured in mcd (millicandela) and as far as I can tell there is no direct conversion........

 

i richt. Thought it would be something like that. I think you are better of in some electronica shop.

 

Lumens and candela are different names for the same unit. A millicandela is 1/1000 of a candela or lumen, therefore 200 lumens is 200,000 millicandela.