Author Topic: anyone ever used a choke for a inductor?  (Read 644 times)

jimitrader

anyone ever used a choke for a inductor?
« on: November 24, 2021, 08:33:38 PM »
anyone ever used a choke for a inductor? I have some of these ..do you think they would work in a wah pedal?also anyone know of a MM that can measure Henries?

Vintage Lowrey Organ Toroid Choke Transformer 500 mh 21447-8
https://i.ebayimg.com/images/g/vLkAAOSwRLxean3W/s-l1600.jpg

R.G.

Re: anyone ever used a choke for a inductor?
« Reply #1 on: November 24, 2021, 08:51:05 PM »
"Choke" is a synonym for "inductor" in the context of electronics. 500mH (or 0.5H) choke is the same as a 05mH/500mH inductor. It should work fine in a wah.

Measuring inductors in the 0.1 H range and above is tough for meters. I don't know of any non-specialized meters that measure this, although they may exist. It's usually easier to put a 0.1uf or so cap across them and then measure the resonant frequency with a signal generator and an oscilloscope.
R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

jimitrader

Re: anyone ever used a choke for a inductor?
« Reply #2 on: November 25, 2021, 12:51:39 PM »
R.G. thanks! how would I connect it since there are 4 lugs?  :-\ will do a follow up later for other builders :icon_smile:

mozz

Re: anyone ever used a choke for a inductor?
« Reply #3 on: November 25, 2021, 01:33:45 PM »
 It may just have 2 pins for each end of the inductor. A meter will tell you if they are connected or dummies.
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PRR

Re: anyone ever used a choke for a inductor?
« Reply #4 on: November 25, 2021, 04:47:17 PM »
...A meter will tell you if they are connected or dummies.

If this is the picture, you can learn a lot by looking.

https://i.postimg.cc/3RcxJgS7/s-l1600.jpg
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Rob Strand

Re: anyone ever used a choke for a inductor?
« Reply #5 on: November 25, 2021, 05:33:28 PM »
There's actually more pics here,
https://www.ebay.com/itm/Vintage-Lowrey-Organ-Toroid-Choke-Transformer-500-mh-21447-8-/324101547759?autorefresh=true

You can see how the wires come out of the coil then go to a pin, then the wire goes from that pin along the top of the mounting plate to a second pin on the same side.

It's very easy to check the terminals  with a DMM.   The duplicate pins will be shorts and the two inductor terminal will show some resistance (somewhere in the 15 ohm to 50 ohm region).

The weird thing is I can't see any bobbin or the windings through the slots in the pot core.   If it wasn't for the seller's high rating I'd be suspicious the coil didn't have any windings!
Send:     . .- .-. - .... / - --- / --. --- .-. -

mozz

Re: anyone ever used a choke for a inductor?
« Reply #6 on: November 25, 2021, 07:21:21 PM »
 I have some similar to those. The outer part is 2 pieces, bobbin is inside. There is a pin or rod through the center and a push type lockwasher holds it together. I've seen some with a bolt through the center. 38 gauge wire i think. You usually crack them if trying to take them apart due to the sealant being like a epoxy type. I have a bunch from some WE (telecomm?) equipment in various values i was trying to take apart to rewind and remember cracking them either taking them apart or reassembling them with a bolt. You tighten the bolt the inductance goes up, adjustable, sort of, until it cracks.
« Last Edit: November 25, 2021, 07:26:25 PM by mozz »
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Rob Strand

Re: anyone ever used a choke for a inductor?
« Reply #7 on: November 25, 2021, 07:43:05 PM »
Quote
You usually crack them if trying to take them apart due to the sealant being like a epoxy type. I have a bunch from some WE (telecomm?) equipment in various values i was trying to take apart to rewind and remember cracking them either taking them apart or reassembling them with a bolt. You tighten the bolt the inductance goes up, adjustable, sort of, until it cracks.
Most epoxies soften at around 150C.   If you heat the assemblies at 100C for a while to ensure the heat has distributed then raise the temp to 150C you can pry them open.   If you bake for too long at 150C you can melt or distort the bobbin, that's why I try to get everything to 100C first.     It's important to have some confidence the surfaces are all hot.  The problem is if there is epoxy on the centre leg it takes a long time to heat through.  Ferrite doesn't conduct the heat well so fan forced is good.   If you tried to open the assembly when it's not hot enough you can crack the side of the core.   Another problem is the heating weakens the ferrite itself so despite the efforts  if you push to hard you can still crack the sides off the ferrite.
« Last Edit: November 25, 2021, 08:21:20 PM by Rob Strand »
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