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Curve tracers

Discussion in 'Electronic Design' started by Joel Kolstad, Jun 27, 2006.

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  1. Joel Kolstad

    Joel Kolstad Guest

    Thinking back to that thread about portable USB-based (faceless) spectrum
    analyzers... is there such a thing as a small, reasonably portable *curve
    tracer* out there? All the curve tracers I've met are those huge Tektronix
    beasts, and it seems as though there ought to be something a little more
    portable & cheaper & readily computer-interfacable...

  2. Joel Kolstad

    Joel Kolstad Guest

  3. It's still more _desktop_ than not and, so far as I can tell, doesn't
    use USB nor did I easily see any means of downloading the gathered
    data into a PC (without a digitizing scope, anyway.) But I've seen
    him posting in the LTSpice group and elsewhere and he seems to be very
    courteous, generous to a fault, and struggling hard to get all the
    important details of his work done correctly and with understanding.

  4. Huntron tracker.

    Many thanks,

    Don Lancaster voice phone: (928)428-4073
    Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
    rss: email:

    Please visit my GURU's LAIR web site at
  5. Joel Kolstad

    Joel Kolstad Guest

    That's why it's only "not half-bad." :) Still a lot better than hugging the
    boat anchor that is a Tek tracer around and all; I think the limitations of
    his design are some I can live with.

    Thanks for your input...
  6. Jim Thompson

    Jim Thompson Guest

    For us Spice modeling aficionados it'd be nice if the data could be
    not only ported to a PC but digitized as V-I pairs.

    ...Jim Thompson
  7. Just this morning I was using my Heathkit 1121 to check some bi-polars
    for a video monitor. Its connected to a Tek 465 but I wonder if it
    could drive into an A-D to get into the PC. As for tracers for the PC,
    how many folks use individual transistors?

  8. Joel Kolstad

    Joel Kolstad Guest

    1) Anyone doing a design where ICs to perform the function don't exist --
    and the volume involved doesn't justify making one (at least where I work,
    this happens *all the time*... I imagine it does for folks like Win as
    2) Folks like Joerg who realize that many a quarter IC can be replaced with
    a five cent discrete circuit.
    3) Those doing high-power designs where discrete devices still dominate.

    I would imagine the IC guys do their "curve tracing" using a handful of FETs
    (or whatever) on a test die being probed by something like a Cascade
    Microtech probe station, a network analyzer, and fancy modeling software...
    at that level everything is huge and expensive anyway.
  9. 4) A customer of mine used a curve tracer to check the connectivity
    of signal lines to BGAs. Not for mass production, but for lab prototypes.
    You can clearly see the protection diodes to vcc and gnd.
    Removed a lot of doubt if sth. did not work as expected.

  10. Here's a cheap way if you have a GPIB card in your PC: go to eBay and
    buy two HP 59501A D/A converters and a HP 34xx digital voltmeter. The
    D/A's give you the base and collector drive voltages. The 34xx you use
    to measure the collector current. A 20-line computer program can cycle
    the D/A's through their ranges and gather the data. With some careful
    shopping you can do it all for under $100.
  11. Jim Yanik

    Jim Yanik Guest

    TEk may still make their 370(Sony/Tek)curve tracers,IIRC,one of those had a
    3.5" floppy drive for storing the displays.they were not huge units like
    the old 576 or 577 curve tracers.As I recall,one of them was smaller than a
    mini-tower PC.
  12. Robert Baer

    Robert Baer Guest

    That is,if you do not have to *pay* $100 per GPIB cable...
  13. I forgot about that part. Find some 24-pin IDC connectors and some
    shielded flat cable and make your own daisy-chain cable.
  14. xray

    xray Guest

    In the 70s - 80s I worked for a large mainframe computer company. The
    models were based on ECL technology. Someone figured that a curve tracer
    was great for telling if a net had its source, load, and resistive
    termination. Any part of the characteristic curve missing indicated a
    bad connection.

    The big Tek curve tracers were spendy for this and 99% of the
    functionality was not needed. One of the engineers whipped togeter a
    little box with an AC transformer, a pot and a resistor or two.
    Connected to the X-Y inputs of a scope you had all you needed. The I
    input on the Y axis of the scope was backwards with the simple
    configuration, but who cares. Good enough for our needs and cheap.

    I made one and use it from time to time for looking at what is connected
    to a net. Many technologies don't have opposite polarity diode
    signatures on the source and load like the ECL did, but it can still be
    helpful, as Gerhard mentions.
  15. Terry Given

    Terry Given Guest

    yeah, but the Tek curve tracer is really handy. It has so far prevented
    my bench from floating away (and has scared off all of the elephants, too)

  16. Fred Bartoli

    Fred Bartoli Guest

    In fact, they are not that big/heavy. I mean, not the 575.
    And how do you get that 1.6kV/100W collector power from your laptop/USB CT
    And how long does it take Tek CTs (no pun) to boot? How often do you have to
    reboot them?
    I guess mine has scared off all the mices as well.
  17. Jim Yanik

    Jim Yanik Guest

    The TEK 7CT11 fits in a 7000 series scope mainframe,and is a nice little
    curve tracer. Then there's the Sony/Tek CTs that are smaller than the old
    575/576/577 models.I can't recall all their model numbers,though. 370 was
    one,but there was one model that was a compact CT,not bigger than a desktop
    PC.the 370 had a microprocessor and a floppy drive for data storage.(might
    have been for configs,not stored test data)

  18. I've bought them surplus for under $5 each. You just have to keep
    your eyes open. The best deal so far was well under $1 each for a batch
    at an auction.

    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
  19. joseph2k

    joseph2k Guest

    O happy day, you have rediscovered the octopus tester. Please see google.
    See also "". How about you find
    the original name for the device.
  20. Guest


    Thanks for mentioning the Curve Tracer. I'm glad that you think that
    it looks useful-enough. And thanks for the kind words, in your earlier
    message in this thread.

    At the risk of encouraging you to buy later rather than sooner, I will
    say that PC/digital interfacing is already on the "to do" list, for the
    Curve Tracer product.

    It will be "a little while", before that is available, though. (I am
    apparently one of the slowest electronic designers to ever have
    existed. But (as I might rationalize, to myself), this is a commercial
    product, as opposed to a personal-use-only one-off. And I have to wear
    a lot of different hats, to get it from a raw design to a shippable
    product. So maybe my development speed is reasonable, after all.)

    I did just finish a fairly-major re-design, and am now in the process
    of trying to ship the new version. Among other things, it finally has
    a nice calibrated base/gate step output, with selectable current or
    voltage steps, which now also has somewhat more power available (150mA
    max @ 15v max step). (Note that "More power!", for both the sweep and
    step outputs, as well as higher voltages, are also already on the "to
    do" list for a future version.)

    The just-completed re-design was originally initiated mainly to make
    the unit easier to build (and maintain, if that's ever necessary).
    But, along the way, most of the sub-systems were also redesigned, for
    better accuracy and precision (some of them with perhaps a bit of
    overkill, heheh). [Yes, I finally got addicted to Spice.] It's still
    a bit of a bear to put one together, for me at least. Or maybe I'm
    just clumsy. And it's all still through-hole, since I wanted to be
    able to offer it in kit form, also. (It's also almost all (gasp!)
    analog.) If I don't say "screw it" and go to surface-mount, soon, I'll
    probably have to make the case larger [or at least the front panel,
    since the main pcboard now sits just behind, and parallel to, the front
    panel (so I could use pcb-mount rotary switches, etc, to eliminate a
    whole lot of discrete wiring)].

    BTW, if anyone else has any suggestions about desirable features, etc,
    I would very-much-appreciate receiving them. I can also be emailed
    directly, at: tomg at .

    By the way, Joel: I saw that you had emailed me, and (I) have been
    TRYING to read it, and respond. But some <expletive deleted> emailed
    me a hundred or more exTREMEly-large emails, a few days ago, making my
    email system temporarily almost-unusable (even on my ISP's web-based
    email service, which is ALL I can even TRY to use, for right now),
    until I can delete more of them, which is VERY-painfully slow, for some
    reason. If I had known that it would take this long, I would have
    temporarily (re)opened a yahoo email account, or somesuch. But, I
    think I should be able to make it usable-enough, soon (I hope), and be
    able to answer your email.

    Thanks again.

    Best regards,


    Tom Gootee

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