Resistor identification?
Moderators: pompeiisneaks, Colossal
Resistor identification?
Hey guys, would any of you that have been around a few blocks know what type of 1/2w 2% resistors these are? I can’t find any info on them or the RC crown logo. Do you know if they are metal or carbon film? I have a bag of them that came out of a beat up old tube organ someone had put out on the side of the road.
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Stevem
- Posts: 4576
- Joined: Fri Jan 24, 2014 3:01 pm
- Location: 1/3rd the way out one of the arms of the Milkyway.
Re: Resistor identification?
If you have a bag of them then sacrifice one of then buy cutting one in half to find out.
Old Carbon comp resistors are a big gamble in terms of them being excessively noisy.
If there Carbon I would ditch them.
Old Carbon comp resistors are a big gamble in terms of them being excessively noisy.
If there Carbon I would ditch them.
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Resistor identification?
These are Rosenthal resistors. Rosenthal later became Draloric. I don’t know about the composition though.
https://www.vishay.com/en/company/brands/draloric/
https://www.vishay.com/en/company/brands/draloric/
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Re: Resistor identification?
If it is carbon comp, heat will make resistance go up, metal or carbon film heat will make resistance go down but the metal film should change less and slower. Can't remember what metal oxide does. I would assume they are carbon film if it's from a tube organ, due to age, but just a guess.
Re: Resistor identification?
Awesome. Thanks for the info! I cut one open to see. I had to whack it with a screwdriver and the other half went flying into the abyss. lol
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Last edited by mauiboy81 on Fri Feb 09, 2024 6:03 pm, edited 1 time in total.
Re: Resistor identification?
It is not carbon comp. I don't think there is a good way to visually tell the difference between film types.
Re: Resistor identification?
Definitely metal or metal oxide film on a ceramic substrate. Given the apparent age and 2% rating, I'd guess MF.
Re: Resistor identification?
Here is one with the coating scraped away.
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Re: Resistor identification?
Film types will look about the same without the coating. Carbon might look slightly less shiny, but maybe not. The closest thing I can think of to a proper test is heat and see what the resistance does. Compare with carbon film and metal film of the same resistance/wattage.
Re: Resistor identification?
Just for comparison I had a carbon film nearby so I scraped the coating away. Unfortunately I don’t have a metal film handy.
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Re: Resistor identification?
Ok cool I will check with heat when I get home from work. Thanks. It’s interesting to me because I have always just purchased different types but have never dug deeper to see differences.
Re: Resistor identification?
Tested a few metal oxide, they are PTC. Some went down in resistance slightly before going up. Not sure why, but my little pink heatgun isn't the most controlled experiment.