Electronic – What do you use to probe small circuits quickly

oscilloscopeprobeprototyping

I still haven't found a really good solution for grabbing tiny surface mount stuff.

  1. Alligator clips are definitely way too big.

  2. Mini-grabbers like this with the spring-loaded hook are an ok solution for bigger stuff, but no good for little surface mount components. I can solder on little bits of wire and then mini-grab those, but it's tedious and time-consuming. And in my experience they tend to be broken more often than not:
    minigrabbers

  3. I got some Tektronix KlipChips and some HP 5090-4356 clips on eBay.
    Tektronix KlipChips and HP 5090-4356
    The Tektronix clips are hard to open, because the plastic head tips to the side and jams instead of sliding down when you try to squeeze it. The HPs don't have that problem. The Tek pincers are made of wire, so they splay out sideways instead of grabbing well (and get permanently bent, making them jam on each other and not close completely, so connections to thin wires are intermittent).
    Wire tips jammed together

The HP pincers are made of thin strips of metal, so they are more rigid in that direction. The wire pincers depend on the bendiness of the wire to overlap each other side-by-side (which doesn't work very well) while the HP pincers fold inside each other, with one a little shorter than the other. This seems to work better, but they get bent outward, and the tubes are plastic, so they get bent outwards by any angular stress and no longer close well.
Tip splayed open
The orientation of the pincers on the HP relative to your fingers is more natural.

These work on SOICs or bigger, but after they've become worn they don't stay on as well. They don't work for surface mount resistors (they just pop off if disturbed even a little) or smaller-pitch ICs.

And I've broken the retractable hook tip for oscilloscope probes by attaching it to a circuit and then letting go, and the weight of the bulky probe and wire put too much stress on the plastic tip and bend it.

Ideally I'd like something that can grip one side of a surface mount resistor, or a pin on a smaller pitch IC, not fall off, not produce any stress on anything, and not break easily. Any advice, ideas, tips, tricks, ingenious alternatives, cheap Chinese knock-offs of better clips?

(Previously asked on xkcd forums and adafruit forums.)

Best Answer

If you're designing your own boards, add test points. Aside from that, soldering on short bits of wire is the best solution I've found so far. I find that the amount of time it takes to strip and solder a wire is far less than what I'd otherwise waste futzing with clips or trying to hold a probe just so while also keeping an eye on a scope.

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