Weird resistor

[sardonic_z]

Hey there folks. Sorry if this is a complete noob question, but I'm really stuck here. I've got a very large resistor (looks to be two or three watts) with a color code that makes no sense whatsoever. It goes, Silver, Red, Green, Red, Silver. One of the silver bands is thicker than the others. It appears to be carbon comp, and it measures out at around 21 ohms, which doesn't seem to square with any sort of way you can interpret those codes. I can't find it in the (apparently) limited schematics that I have. Also, it's probably between forty and fifty years old and as best I can figure seems to be the weak link in a power regulation circuit, so I suspect it has probably drifted significantly over the years. The lead broke at the body on one side pretty much as soon as I touched it, and I need to get a replacement.

Any ideas?

 

[KJ6EAD]

It's probably a 2500μH 10% inductor.

 

[sardonic_z]

ahh that would explain a few things.. least of all why I can't seem to find it anywhere on the schematic. I had forgotten that inductors look like resistors sometimes. Well, given that it's very large in diameter, do I need to worry about any sort of maximum current rating?

(sorry if that's a dumb question, but I have very little experience ordering inductors.)

 

[KJ6EAD]

In most applications, anything with the right inductance and of similar physical size should be adequate. Can you make any assumptions about current based on other connected components?

If you look at the Hammond 2.5mH axial leaded inductors listed on Digikey, you'll see 3 current ratings, 50mA, 125mA and 250mA. Of those three, the 50mA model has a DC resistance very close to what you measured but physically, the 250mA model is most similar to what you had. I'd get the big one since a higher current rating is usually better but you need to evaluate based on the context of the circuit.