[Boatanchors] Choke Info Needed

[Carl]

Characterising is not the same as confirming the static inductance. Dont mix 
apples and oranges.

Carl


----- Original Message ----- 
From: "J. Forster" <jfor at quik.com>
To: "Carl" <km1h at jeremy.mv.com>
Cc: "Mark K3MSB" <mark.k3msb at gmail.com>; "List Boatanchors" 
<boatanchors at mailman.qth.net>; "Kenneth D. Grimm,K4XL" <grimm at sbc.edu>
Sent: Thursday, October 08, 2009 7:35 PM
Subject: Re: [Boatanchors] Choke Info Needed


> If you want to characterise a swinging choke, a single point measurement
> at zero bias current is insufficient.
>
> There are bridge configurations that allow inductance measurement vs.
> current bias, just as there are to measure capacitance as a function of
> bias voltage.
>
> Some of the older GR bridges include this feature. I think the 1650s did
> for example.
>
> -John
>
> ==============
>
>> Chokes are specified at no load in most catalogs. All the known ones Ive
>> measured with a handheld LCR meter ar right on.
>>
>> Carl
>> KM1H
>>
>>
>> ----- Original Message -----
>> From: "J. Forster" <jfor at quik.com>
>> To: "Mark K3MSB" <mark.k3msb at gmail.com>
>> Cc: "List Boatanchors" <boatanchors at mailman.qth.net>; "Kenneth D.
>> Grimm,K4XL" <grimm at sbc.edu>
>> Sent: Thursday, October 08, 2009 6:36 PM
>> Subject: Re: [Boatanchors] Choke Info Needed
>>
>>
>>> Did you measure L as a function of current through the choke? It does
>>> not
>>> sound like it.
>>>
>>> -John
>>>
>>> ===============
>>>
>>>
>>>> Well,  I checked again and came up the same info.
>>>>
>>>> I was looking for a 4-12 H 300 mA swinging choke, and a friend of a
>>> friend said he had one, and I picked it up last night.
>>>>
>>>> It's about 18 ohms DC resistance,  and the inductance measures around
>>>> 2H
>>>> (using the bridge on my IT-28,  which isn't too bad surprisingly).
>>>>
>>>> Since inductance is inversely proportional to current in a swinging
>>> choke, I don't think what I have is a swinging choke.
>>>>
>>>> Mark K3MSB
>>>
>>>
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>>
>
>