Choke ID - Page 1
Forum section: electronics / beginners

author: registereduser
author_rank: Contributor
timestamp: October 15, 2023, 05:06:11 pm
content: Can anyone know the value of this choke from a small AM/FM radio?

author: janoc
author_rank: Super Contributor
timestamp: October 15, 2023, 05:12:56 pm
content: * janoc gets out a crystal ball, gazes into it for 5 minutes and then: "100nH! That is for sure 100nH!"I.e. with the information you have posted that's about as good and accurate answer as you will get. Blurry photo of a part of a board of some unknown radio, with no model number, no readable markings anywhere, good luck. Or that crystal ball ...If you want to know the inductance, desolder it and measure it.

author: Gyro
author_rank: Super Contributor
timestamp: October 15, 2023, 05:48:51 pm
content: Quote from: janoc on October 15, 2023, 05:12:56 pmWell I very much doubt that it would be 100nH, whichever direction you read it, it's got a green dot so there's a '5' in there.Assuming that the black end is the multiplier, then my crystal ball says maybe 15uH, but yes, unless you can find a body code reference, the only way to be sure is to measure it. I've no idea if the main body colour has any relevance (or whether the black end is actually uH).

author: Neomys Sapiens
author_rank: Super Contributor
timestamp: October 15, 2023, 06:13:25 pm
content: Should be like this when in the shown form factor:

author: janoc
author_rank: Super Contributor
timestamp: October 15, 2023, 06:56:02 pm
content: Quote from: Gyro on October 15, 2023, 05:48:51 pmAssuming that's actually green and not e.g. blue. No telling with that underexposed picture.I do wonder why is it so difficult for people to check the photo they took and verify that it is exposed properly, with enough light and actually having the relevant bits in focus? And if it is not OK, retake the picture? This seems to be an universal problem, despite pretty much everyone having an expensive smartphone with cameras that would put DSLRs from a few years ago to shame.

author: registereduser
author_rank: Contributor
timestamp: October 16, 2023, 01:50:18 am
content: Quote from: janoc on October 15, 2023, 06:56:02 pmI'm sorry my phone is not up to your standards, it is all I could afford. First dot is maroon, I guess the second dot is dark green, then big black 'dot' or whatever covers whole side.Here is another picture, this is as good as I can get.

author: janoc
author_rank: Super Contributor
timestamp: October 16, 2023, 06:28:28 pm
content: Quote from: registereduser on October 16, 2023, 01:50:18 amPlease go and re-read the comment you are quoting.I am pretty certain even a cheap phone from years ago can take a well lit and reasonably in focus photo unless you have a millimeter of finger grease on the lens. That's not a function of the phone but of the person holding it.Quote from: registereduser on October 16, 2023, 01:50:18 amThat's quite a bit better. Sufficient light is important if one needs to identify colors.Quote from: registereduser on October 16, 2023, 01:50:18 amThat might be 15uH (brown-green-black), as Gyro said, but no telling without knowing what is the model number/manufacturer of it and not knowing what is it used for in that circuit (some LC tank/filter given that it seems to have a cap in parallel?). If you need to know, desolder it and measure it.

author: Gyro
author_rank: Super Contributor
timestamp: October 16, 2023, 06:44:32 pm
content: From the diagram that Neomys Sapiens posted, it looks like they follow an E12 series (I can't see bog standard inductors going to E24) so I think the only value with green as the second digit is 15 (or some decade multiple).