Inductors L1...L12, can sameone identify these? - Page 1
Forum section: electronics / general

author: Finderbinder
author_rank: Regular Contributor
timestamp: September 18, 2025, 09:35:06 am
content: There are no other markings on these. Are they any good for something?

author: Roehrenonkel
author_rank: Frequent Contributor
timestamp: September 18, 2025, 10:07:42 am
content: Hi Finderbinder,looks like some calibration-/range-Inductors.Maybe from a (grid-/gate-)dip-meter?Do not scrap them.BestEdit: scRap

author: Finderbinder
author_rank: Regular Contributor
timestamp: September 18, 2025, 10:15:24 am
content: Any clue where to find specifications of these?

author: Roehrenonkel
author_rank: Frequent Contributor
timestamp: September 18, 2025, 11:05:46 am
content: Hi,....no, more info please: Photos of the cans, the box, etc...What resistance do you meassure?Edit: The grey colour looks like GenRad/General-Radio.

author: picburner
author_rank: Frequent Contributor
timestamp: September 18, 2025, 11:16:05 am
content: Quality factor meterBM560

author: Finderbinder
author_rank: Regular Contributor
timestamp: September 18, 2025, 11:22:57 am
content: Seems they are not precise at all+-20% regarding manual:https://printsip.ru/download/new16/bm560.pdf

author: picburner
author_rank: Frequent Contributor
timestamp: September 18, 2025, 11:38:32 am
content: The technical data for the 12 inductors is attached.The manual specifies that they cannot be used as metrological references.

author: EC8010
author_rank: Frequent Contributor
timestamp: September 18, 2025, 01:18:38 pm
content: Presumably, you don't have the BM560 Q-meter to go with them and someone, somewhere, is cursing the loss of the inductors for their meter. But what you do have is a bunch of very nice screened cans with quality connections. it's just a pity the connection is only two wires, not four. There must be a use for such cans even if it's not the original one.

author: Finderbinder
author_rank: Regular Contributor
timestamp: September 18, 2025, 01:20:39 pm
content: Quote from: EC8010 on September 18, 2025, 01:18:38 pmJust was typing while you posted...but maybe these are a good base (metallic case) for something metrological/precise/interesting?Any ideas?

author: EC8010
author_rank: Frequent Contributor
timestamp: September 18, 2025, 03:12:15 pm
content: First thought was to put reference capacitors in the can, but the cans are the wrong size/shape to take four BNCs spaced 22mm apart (to fit standard LCR tester).I think it all hinges on you being able to find some more feed through connectors. If you can, one possibility is to line the can with 2mm EVA foam and put a voltage reference inside. The cans look quite large, so there might be enough room for the voltage reference to go in a temperature-controlled can within the outer can.

author: PrecisionFreak
author_rank: Contributor
timestamp: October 11, 2025, 02:17:22 pm
content: I made an OCR optical character recognition (tab separated) of the coil data, ready to be copied to an calculation sheet, see the appended file.3.25. Technical data of the 12 coils which form the set.Coil F_low F_high Q_low Q_high C_high C_low inductivity inherent deviationNumber MHz MHz 1 1 pF pF µH pF pF1 0.05 0.08 85 115 350 130 30000 8.6 2.52 0.08 0.14 140 180 360 110 12000 10 2.53 0.14 0.24 160 210 330 105 4300 8.5 2.54 0.24 0.44 170 210 410 115 1150 9.5 2.55 0.44 0.75 190 240 420 140 330 8.5 2.56 0.75 1.30 165 220 410 130 120 7.0 2.07 1.30 3.00 170 210 400 70 40 7.0 2.08 3.00 5.00 200 230 210 70 13,5 6.0 2.09 5.00 8.00 200 240 170 66.5 6.5 5.8 2.010 8.00 14.0 295 400 255 80 1.6 5.3 1.511 14.0 24.0 350 400 130 40 1.0 4.0 1.512 24.0 35.0 370 420 80 35 0.55 3.5 1.5

author: coppercone2
author_rank: Super Contributor
timestamp: October 12, 2025, 05:52:10 am
content: some old equipment uses socketed inductors for range adjustments. Like high quality stuff from 1950you can easily add terminals by drilling holes and installing terminals, if you want 4 wire. Be sure to make a template if you drill out all of them so they all fit in the same socket, and you can replace the blades with pins or whatever you please. Just takes some shopping around to find the right thing. Insulated turret terminals, insulated pin terminals, etc