01-09-2015, 10:56 AM
(31-08-2015, 09:23 PM)Nick Wrote: I'm not sure how you can have a table of maximum continuous working voltage that holds for all resistors of all types from any manufacturer when the LEV is independent any calculation - you've just used typical LEVs for a given power rating but the actual LEV is that stated by the manufacturer for that series of resistors and may or may not be the "common" value... e.g. tje Welwyn RC55 250mW series have a LEV of 350V, not 250V and when SMDs are considered, all bets are off...
I doubt you'd be buying Welwyn RC55 resistors at ten for a penny, Nick! That is, after all, what we are discussing here.
My table was - and still is - intended as a generic guide, the maximum voltages being taken from a manufacturer's data sheet for typical run of the mill resistors.
It's a damn site more intuitive than putting 450V across a resistor to see what happens!
I would expect anybody with special requirements to research manufacturers' data sheets for the correct component.
The formula I used, as you surmised, is V = √PR where P is in watts and R is in ohms.
