[ARC5] [Milsurplus] BC-348-Q Capacitor Questions

[Dennis Monticelli]

Better to buy the instrument with its probe for sure.  You can,
however, find the probe by itself on eBay, though standalone probes are a
lot less common than standalone boxes.  I don't think I've mentioned it yet,
but you calibrate the instrument together with the probe as a system.  Once
calibrated the probe is not freely interchangable with other 428's like a
scope probe would be (which only needs a little capacitance tweak when
changing scopes).

The 428 A and B are very close electrically and I know that the probe is the
same.  As I recall the only difference is that the B has the high current
range (10A) and a degaussing port in the rear to restore the head after it's
been subjected to the high field induced by 10A.  Rack or bench top, the
instruments were the same.

One other interesting factoid is that the instrument is so sensitive that if
you open the jaws of the probe and orient it toward the earth's magnetic
field, it will register as about 0.5A on the meter.  Inasmuch as you can
measure 0.0005A with precision on the 428, this means that the closed
magnetic circuit of the flux-gate amplifier is allowing accurate
measurements at 1/1000th of the earth's mag field.  That's impressive!

Dennis AE6C

On Mon, Aug 23, 2010 at 12:20 PM, Roy Morgan <k1lky at earthlink.net> wrote:

>
> On Aug 23, 2010, at 6:48 AM, <arc5 at ix.netcom.com> wrote:
>
> >
> > ----- Original Message -----
> > From: "Dennis Monticelli" <dennis.monticelli at gmail.com>
> > Subject: Re: [Milsurplus] [ARC5] BC-348-Q Capacitor Questions
> >
> >
> >> I find that it is easier and less invasive to use an old HP 428
> >> clip-on
> >> current meter to check caps.....
> >
> > Coolness, Dennis.  I gotta get me one.
>
> Make sure you get the probe.. or the thing is useless.
>
> Roy
>
> Roy Morgan
> k1lky at earthlink.net
> K1LKY Since 1958 - Keep 'em Glowing!
>
>
>
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