[ARC5] BC-348-Q Capacitor Questions

[Henry Mei'l's]

Thank you Ray,

I remember something about the Hall effect from my physics studies -- also 
know that it is used in electronics - I'll  open up my theory books --
something to do with  cross surface elecron or  magnetic flow effects due to 
current flow, as far as I can remember.

Dennis is very good at explaining things in a very specific way -- so if he 
has an alternative solution, I'd  still like to see it.

Clamp on power line current testers are dependent on AC flux -- I imagine--  
whereas were dealing with
DC  current here.

Henry

----- Original Message ----- 
From: "Roy Morgan" <k1lky at earthlink.net>
To: "Discussion of AN/ARC-5 military radio equipment." 
<arc5 at mailman.qth.net>
Sent: Monday, August 23, 2010 8:25 AM
Subject: Re: [ARC5] BC-348-Q Capacitor Questions


>
> On Aug 23, 2010, at 2:08 AM, Henry Mei'l's wrote:
>
>> Hello Dennis
>>
>> How does this work?I don't have an HP 428 but is there some way I
>> can rig up
>> something using standard VTVMs/VOMs &/or scopes to do the same thing?
>>
>> ----- Original Message -----
>> From: "Dennis Monticelli" <dennis.monticelli at gmail.com>...
>>> I find that it is easier and less invasive to use an old HP 428
>>> clip-on
>>> current meter to check caps.
>
> Basically, here is how the HP clip-on milliammeter works:
>
> The clip on probe contains a magnetic core that is placed over the
> wire being tested.  The core is operated at a certain level of
> magnetic flux by the instrument.  The DC current in the wire under
> test, changes the flux in the core.  This change is detected by the
> instrument and there is a corresponding reduction of the flux in the
> core to return it to the original balanced state.
>
> So, the important parts of the system are:
>
> A unique clip-on core
> A source of magnetism in the core that is monitored by the instrument
> A feedback system to reduce the magnetism to restore the original flux
> level
> A metering system to display the detected current.
>
> Note: if you buy one of these HP meters without the clip-on probe, you
> have a useless piece of equipment.
>
> There are clip-on probes meant for use with oscilloscopes that detect
> AC currents in a wire, and may well be some that detect DC currents.
> Tektronix, naturally, had/has such AC detecting probes. The one I know
> of is quite old now, and had a little power supply and amplifier as
> part of the setup.  It's frequency response was modest, but I think it
> worked at line current and up to perhaps some couple of hundred kc.
>
> I have a couple of devices that are called "Hall Effect sensors".
> These things are based on relatively new creations of modern physics
> that I don't understand, but I think they detect current in a wire
> that is passing through the opening in the thing.  Search via Google
> for "hall effect sensors" and you'll get lots to read. Apparently, you
> can buy them at Digi-Key.  This seems to be a promising avenue to
> explore.
>
>
> Roy
>
> Roy Morgan
> k1lky at earthlink.net
> K1LKY Since 1958 - Keep 'em Glowing!
>
>
>
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