"N_Cook"

When did they first arrive and do they always have an unusual body colour?
There is a patent reference to 1977 but when would the first appearance in
domestic equipment have been ?.
Resistors that fail open circuit if a designed-in current capacity weak
point is exceeded , fuse-fashion, not just the thermal limit of the body ,
so often no overheating discolouration to the body or surrounding board


** Genuine "fusible "resistors with specific fuse current ratings are rare
beasts - the only ones I know of were used by Yamaha in some of their 70s
and 80s audio amplifiers and were all miniature wire wound types.

OTOH - what are nowadays laughingly referred to as "fusible resistors" are
simply "flame proof" resistors - typically ordinary 0.5W & 1W metal film
types with a high temp, flame proof coating in lieu of the incendiary paint
coatings normally used.




..... Phil