#garfield Logs

Jan 21 2023

12:37 AM rue_mohr: marking codes:
12:47 AM rue_mohr: 13T
12:47 AM rue_mohr: KNM
02:39 PM rue_mohr: oh I'm supposed to go look for those...
03:53 PM aandrew: https://hackaday.io/project/180791-h7rtx that's actually pretty cool
03:54 PM aandrew: rue_mohr: so you bin them by k, where k = uh/n^2, uh = inductor value in microhenries and n^2 is the number of turns, squared?
04:14 PM aandrew: I mean I know about k for *coupled* inductors but that's not this
06:59 PM rue_mohr: yes
06:59 PM rue_mohr: so, the permeability is loosely related to the saturation flux
06:59 PM rue_mohr: and by the time you have those your kinda there
07:00 PM rue_mohr: losses are really the only other thing to get a grip on, but its generally related to how hard you drive the material
07:43 PM aandrew: very interesting... so if I put 10 turns around an unknown toroid, measure the inductance, compute uh/100 and bin them
07:43 PM aandrew: I should do that a few known materials and see
07:45 PM rue_shop3: yep
07:46 PM rue_shop3: p.s. 10 turns is kinda dodgy, I recommend like 15-20 if you can
07:46 PM rue_shop3: well, for my meter it is anyhow
07:47 PM rue_shop3: (chineese transistor tester)
07:52 PM aandrew: right probably
07:52 PM aandrew: I made my milliohm meter and it seems to work ok
07:53 PM aandrew: ended up buying an RCL meter and it happens to have a decent mOhm feature, so I did some testing between them and my shitty arduino version seems to track quite well
10:20 PM rue_shop3: cool
10:27 PM aandrew: this RCL meter is kind of neat, it'll measure the Q of inductors and dissipation factor of caps too
10:34 PM aandrew: man I fucking love good tequila
11:53 PM rue_shop3: 1 tequila, 2 tequila, 3 tequila, floor... :D
11:55 PM rue_shop3: I have a 4M rom here with LOTS of free spaces