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Multimeter with inductance?

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  • Helmholtz
    replied
    The split receptacle contacts act as switches. Without them (or a separate switch) 4-wire operation via the blade contacts would not be possible.

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  • Joe Gwinn
    replied
    Originally posted by Helmholtz View Post
    I looks as if the meter is laid out for 4-wire operation, i.e. separate current source and voltage measuring circuits. As it also allows 2-wire measurement, the banana receptacles need to provide a shorting function when inserting a normal banana plug to connect source and meter circuits.
    In other words, the split contact banana receptacles are necessary to allow 4-wire measurement with no bananas inserted.
    Once banana plugs are inserted into the +/- receptacles and the 2 halves are shorted, the 4-wire system is converted to a 2-wire configuration.
    That's exactly right.

    IET no longer sells the DE-5000 (or its successor DE-6000?), but here here is the IET manual (from 2011) on the DE-5000: https://www.ietlabs.com/pdf/Manuals/DE_5000_im.pdf

    It appears (page 37 top) that the split-pin banana jacks are used only to compensate paths within the instrument, so no split-pin dual banana plugs are used or provided.

    IET also provides a 78-page primer on LCR measurements: https://www.ietlabs.com/pdf/applicat...%20Edition.pdf

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  • Helmholtz
    replied
    I looks as if the meter is layed out for 4-wire operation, i.e. separate current source and voltage measuring circuits. As it also allows 2-wire measurement, the banana receptacles need to provide a shorting function when inserting a normal banana plug to connect source and meter circuits.
    In other words, the split contact banana receptacles are necessary to allow 4-wire measurement with no bananas inserted.
    Once banana plugs are inserted into the +/- receptacles and the 2 halves are shorted, the 4-wire system is converted to a 2-wire configuration.
    Last edited by Helmholtz; 12-29-2018, 05:37 PM.

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  • g1
    replied
    Originally posted by nosaj View Post
    Looks like your stuck using the tl-21 adapter and modifying a set of kelvin cables.
    Could not find what your asking for.
    http://dexterslab2013.blogspot.com/2...onversion.html
    nosaj
    Yes, I think this is the only way. I could not find any such thing as a 'split' single banana plug. All searches turn up 'dual banana' plugs, which is a different thing.
    I have no idea how they came up with the receptacles (split single banana) on the meter itself and what plug is supposed to mate with it. And if there were such a plug, what would prevent it from rotating so it shorts the 2 sides together?

    So, technically, this meter supports 4 wire measurement, but there are no commercially available accessories to do so unless you build your own.

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  • nosaj
    replied
    Looks like your stuck using the tl-21 adapter and modifying a set of kelvin cables.
    Could not find what your asking for.
    http://dexterslab2013.blogspot.com/2...onversion.html
    nosaj

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  • g1
    replied
    So can anyone link a 4 wire probe set that will work with these split banana or the double sided blade terminals?

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  • Joe Gwinn
    replied
    Originally posted by g1 View Post
    Thanks nosaj.
    Split banana's are definitely new to me. Still think it's very odd there is no mention of it or of an accessory available in the instruction manual.
    This trick came from General Radio, from which the DE-5000 design came.

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  • Joe Gwinn
    replied
    Originally posted by g1 View Post
    It does not seem to have kelvin 4 wire capability. It has 2 probe ports and 'shield'. Only 3 terminals of the meter are used at a time.
    On the adapter, the 3 blade terminals are used, the other 3 are 'dummies' and only used for physical support.

    [ATTACH=CONFIG]51686[/ATTACH]
    Yes it does have four-wire support. I have one too. The flat blades have copper on the two sides, and glass-epoxy PWB material between.

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  • g1
    replied
    Thanks nosaj.
    Split banana's are definitely new to me. Still think it's very odd there is no mention of it or of an accessory available in the instruction manual.

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  • nosaj
    replied
    Back side of PCB note the 3 connection points at the bottom 2 are split to allow for Kelvin measurements
    Click image for larger version

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    The last link I posted I think is easier to consume than the video by Dave from eevblog.
    nosaj
    Last edited by nosaj; 12-28-2018, 11:44 PM.

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  • g1
    replied
    Originally posted by Reader View Post
    I think the blades are one sided edge style connections made of PCBoard material. I could not find a photo showing the other side of those blades. That would clear up the situation.
    You are correct. I took my TL-21 apart. Sorry I can't post a photo right now.
    What I don't understand is why there is no 4 probe accessory and no mention of 4 wire Kelvin type measurement in the operation section of the manual?
    Unless those 3 slots are a standard type connector, there is no way to hook up 4 probes.

    (edit: I do still need to watch that EEV video, hopefully it will clear everything up)

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  • nosaj
    replied
    Originally posted by Reader View Post
    I think the blades are one sided edge style connections made of PCBoard material. I could not find a photo showing the other side of those blades. That would clear up the situation.
    This tear down thread should explain it the jacks are split to allow for kelvin measurements.
    https://www.eevblog.com/forum/testge...-and-teardown/Click image for larger version

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    nosaj

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  • Reader
    replied
    Originally posted by Helmholtz View Post
    This would make sense. It means that the two contacts on the blades are separated by some insulating carrier. Not obvious to me from the pictures.
    I think the blades are one sided edge style connections made of PCBoard material. I could not find a photo showing the other side of those blades. That would clear up the situation.

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  • Helmholtz
    replied
    Originally posted by Reader View Post
    The tear down article referenced in post #24 seems to indicate that there are 2 contacts on each of the + and the - blade contacts. Therefore, it's likely that the adapter box does provide true 4 wire connection. The dual contacts are visible in the photos in post #24. (Same photos as used in the tear down article)
    This would make sense. It means that the two contacts on the blades are separated by some insulating carrier. Not obvious to me from the pictures.

    Leave a comment:


  • Reader
    replied
    The tear down article referenced in post #24 seems to indicate that there are 2 contacts on each of the + and the - blade contacts. Therefore, it's likely that the adapter box does provide true 4 wire connection. The dual contacts are visible in the photos in post #24. (Same photos as used in the tear down article)

    Leave a comment:

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