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HP 456A AC supply xfrmr ?

Discussion in 'Electronic Components' started by Henry Kolesnik, Feb 17, 2004.

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  1. I need to find or build an AC supply for the HP 456A AC current probe. The
    factory optional AC supply has B+ at 5.4 VDC at 5.5 ma, and the B- is 8.1
    VDC at 20 microamps! (Mine has dead mercury batteirs that supplied 8.1 and
    5.4) HP used a small centrer tapped transformer that shows 25 VDC on the
    output of a 1/2 wave bridge( 2 1N38A diodes) that is regualted down to the
    8.1 and 5.4. using a 2N650 pass transistor and a 14 volt zener(updates show
    it at 6.8 v). I can't find anything on the physical size of the xfrmr but
    it has to be no bigger than end of ones thumb, or maybe they used a wall
    wart but I kind of doubt it. I've not had any experience with real small
    low current xfmrs that take 115VAC to 20 or 30 VAC and would appreciated
    any ideas on what to use. A wall wart would be my last resort. I'd like to
    fit the xfmr in the current probe case which has space for something about
    an inch tall.
    hank wd5jfr
  2. dated Tue, 17 Feb 2004 09:45:05 -0600,
    A wall wart would be much safer.
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