Any simple way to id resistor types? - UK Vintage Radio Repair and Restoration Discussion Forum

ColinTheAmpMan1 · 6th Mar 2018, 9:16 pm

Hi,
This may be a wild-goose chase, but who knows? The members of this forum often amaze me with their knowledge and expertise.

I have a huge stock of resistors that I am probably wasting my time sorting, but it is challenging me

. These resistors are of all types and appearances and I wonder if there is any way to identify them by appearance? There are of something like three different sizes; I am guessing that the ones which are about the size of a grain of wheat are probably 0.125W metal-film types. There are some much larger ones which I guess are probably 0.25W or 0.5W, possibly higher wattage, but unknown type. The vast majority are pretty much the same size, but some are dog-bone shape, with slightly bulbous ends and some are cylindrical with square ends. These last ones are pretty much all moulded in some sort of brown plastic, as the moulding seams are often visible. The dog-bone types have painted bodies in a variety of colours from pale grey to buff, though many are a bright pale green colour. I am guessing again that they are all metal-film or carbon-film, with no carbon-composition types at all. Is there any way that I might identify the metal-film ones from carbon-film? This isn't just idle curiosity, as I would guess that the intrinsic inductance would differ between the types and there might be other reasons why one type may be preferred over another in some situations.

I could supply picture of typical ones, but it may not be worthwhile if I am chasing wild geese....

Colin.

6th Mar 2018, 9:16 pm	#1
ColinTheAmpMan1 Octode Join Date: Jan 2012 Location: Wimbledon, London, UK. Posts: 1,465	Any simple way to id resistor types? Hi, This may be a wild-goose chase, but who knows? The members of this forum often amaze me with their knowledge and expertise. I have a huge stock of resistors that I am probably wasting my time sorting, but it is challenging me . These resistors are of all types and appearances and I wonder if there is any way to identify them by appearance? There are of something like three different sizes; I am guessing that the ones which are about the size of a grain of wheat are probably 0.125W metal-film types. There are some much larger ones which I guess are probably 0.25W or 0.5W, possibly higher wattage, but unknown type. The vast majority are pretty much the same size, but some are dog-bone shape, with slightly bulbous ends and some are cylindrical with square ends. These last ones are pretty much all moulded in some sort of brown plastic, as the moulding seams are often visible. The dog-bone types have painted bodies in a variety of colours from pale grey to buff, though many are a bright pale green colour. I am guessing again that they are all metal-film or carbon-film, with no carbon-composition types at all. Is there any way that I might identify the metal-film ones from carbon-film? This isn't just idle curiosity, as I would guess that the intrinsic inductance would differ between the types and there might be other reasons why one type may be preferred over another in some situations. I could supply picture of typical ones, but it may not be worthwhile if I am chasing wild geese.... Colin.