[Boatanchors] Choke Info Needed

[Carl]

Unecessary waste of time since there are graphs in many handbooks that tell 
all that is needed to build a successful PS..

Carl


----- Original Message ----- 
From: "J. Forster" <jfor at quik.com>
To: "Carl" <km1h at jeremy.mv.com>
Cc: "List Boatanchors" <boatanchors at mailman.qth.net>; "Kenneth D. Grimm, 
K4XL" <grimm at sbc.edu>
Sent: Thursday, October 08, 2009 11:18 PM
Subject: Re: [Boatanchors] Choke Info Needed


> Characterizing is measuring the incremental inductance as a function of
> bias current. That is essential information to calculate the impedance of
> the choke vs. current and hence the regulating effect when used as a
> swinging choke.
>
> Apples and apples.
>
> -John
>
> ================
>
>
>
>> 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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>>>>
>>>
>>>
>>
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