I know we were talking in the meeting with Rigol about an ultra-high performance current clamp, but do we have one of any kind?
I need one with 20-30kHz of bandwidth and that would be great if there is one available.
Thanks!
well, there is a Tek one on the probe hanger, it goes with the matching amplifier on the rack below - but the mechanical slide is broken so it is stuck closed.
it would be great if it worked - I used one just like it years ago - cost several thousand new with the amp - it was one of those tools you didnāt need very often, but when you did it was a lifesaver.
hmm, perhaps you could snake a wire through the clamp, and see if it works. itād be a little inconvenient, but perhaps thatās even good enough for your purposes. and if it works, then we can consider a little surgery and perhaps some 3D printed replacement parts to get the clamp slide operable. i priced some used copies on ebay a couple months ago - i recall they were going for around $400 without the amplifierā¦
hereās a copy of some findings and (slower BW) alternativesā¦
cottjrFeb 28
hereās a working version on eBay of the one at the space. They want $338 for probe by itself, without the amplifierā¦
check out the specs - 50 MHz BW up to 20 Amps. Sweet eh?
and hereās a non-working probe for parts for $200 - crazy
check out Tekās ācurrentā lineup - cool options - but you get what you pay forā¦
I picked up one of these Hall effect versions last year and played around with it a littleā¦
thereās also the shunt method with a little higher bandwidth than the hall effect one
and - looks like sparkfun also has this version:
I wonder how well it does at low currents and wide bandwidthsā¦ It might be fun to try for just $10
Those Allegro current sensors are neat, but theyāre definitely not lab quality. I will probably end up buying a few of them to work with at some point anyway though.
Thanks for the feedback on it. I was hoping there was one sitting around ready to use, but alas!
Ok, Iāve managed to un-break the probe a little bit. You can slide the lock back and forth with a small screwdriver and lock and unlock it at will.
But.
It still doesnāt seem to pass signal. I think the problem is in the probe connector or the amplifier, but Iām not sure where. Does anyone have a service manual or schematics (or know where to get them) for a Tektronix AM 503A Current Probe Amplifier?
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This might be what your loooking for.link
Thank you gentlemen for working on getting the probe working (or not). We have some money in our budget but wasnāt really planning on spending it one tool. There is so much still left to get done. If it can be repaired great, but if we have to punt and purchase one let me know.
Have you found the needed hints to setting gain correctly?
As I recall, the scope needs to be at a certain v/div, and even with that it was sometimes annoying to get the probe amp on the right scaleā¦
Always fun when there are multiple controls in seriesā¦
There is no output at all, that I can tell. I messed with it for a couple of hours, but I havenāt tried again yet.
That is, there is signal to the scope, and changing settings on the amp changes outputs, but no current waveform signal shows up on the scope.
Hmm - Iāve been itching to fire that thing up and see what I can remember. But I havenāt had a good enough excuse yet, and I canāt get there until Sunday or Monday to lend a hand.
First thing Iād try is to get a current limiting supply, set it for one or two amps, make sure probe amp and scope are both DC coupled, make sure the clamp was on its āfully locked/closedā position, and see if I could detect such a large current by manually connecting/disconnecting the wireā¦ Wish I could remember more details but itās been quite a whileā¦
Gut check - youāre only placing one leg of a current loop through the clamp - right? e.g. Not both conductors of a twisted pair or coaxā¦
I appreciate the help, but I used to have one very similar to this, except it connected directly to the accessory port of the scope. I think Iāve gotten past all of the headsmack items, but you never know.
Cool - just checking. Thanks for digging into the unit. Too bad the prognosis is ākaput / no workieā, but good to knowā¦
GOOD NEWS EVERYONE
It looks like I spoke too soon. I am getting both AC and DC response out of the probe/amp. The āDC Levelā knob doesnāt appear to do anything that I can tell though.
It doesnāt appear that you need to lock the probe to get a result, so I would recommend just not fiddling with that part for now.
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It really is amazing what a good night of sleep will do for youā¦
The āDC Levelā knob can be used to center the signal when in AC mode. For some reason it doesnāt auto-center, so you use that knob to move it around. It has no effect in DC mode.
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Way cool!
Great to know that tool is available, despite itās somewhat confusing controls.
Canāt wait to hear if/how-well it helps with your project, and if you think itās worth the effort / risk to operate on the clamp mechanicsā¦