Does adding an alligator clip to a multi- /Ohmmeter change the reading?

I need to use an ohmmeter to measure the resistance between two points, and if it’s about 10 ohms do one thing, if not, do another. I’m using a basic Extech multimeter that has pointy-pointy test leads. It’s next to impossible to make contact on both points, so I’d like to jam the test leads into a pair of alligator clipsfrom Radio Shack[sup]*[/sup] and clip them on. This may be a silly question to anyone who knows anything about electricity, but will this change the measurement outcome? Change it to the point where the measurement is useless?

Broken appliances make for great learning experiences.

[sup]*I’m kind of beside myself on this one—my mall Radio Shack not only knew what they were, but had a whole draw full of them. [/sup]

The clips will add a few micro ohms of resistance - much less than the test leads themselves.

Adding the clips will add a tiny fraction of an ohm to the resistance - far less than enough to affect the measurement.

Three and four minutes to answers. Man, I love this place.


As long as the connection between the probe tip and the gator clip is tight and clean, there should be no more than a few milliohms of resistance from the connection. If you were measuring very weak circuit board levels, it could screw things up, especially with capacitance loading. If you’re working with appliances where measurements within an ohm or two and a few millivolts are close enough, you’re fine.

how bright and shiny are your clips?

you can buy sets of leads (the wires that plug into the meter) with all sorts of ends. some come with clips that the pointy tips plug into to do that.

just make sure there is a tight and clean fit.

My partner in electronics lab was the best in design and calculation.
We were told to quit using 1% resistors, so we bought 10% by the dozen, and measured out the best ones. This smart guy, best in the class, would hold the test lead probes to the resistor leads with his bare hands, thus putting 47K in parallel with the resistor he was measuring. :slight_smile:

As he said above, you are adding an insignificant amount of resistance.

And regardless of what type of leads/clips you’re using, you should “zero” the meter by connecting the leads together before you take your resistance measurement. At this point you can either a) note the reading and subtract this reading from your resistance measurement, or b) press the relative button on your meter.

You have a better VOM than I. :slight_smile:

…Gunga Din!

that’s the well known German brand.

Probably Fluke. I got to use one in the lab.
Sure as hell can’t afford one.

In my e-designer days, my Fluke 8020 was my prized possession… I remember buying it and using it like some people remember their first car. It was one of the ones that slowly succumbed to LCD rot, though, and I never had the time to get a replacement display. Use $10 cheapies these days that are almost as good if not as reliable and accurate. But I Remember…

As they told me in back in A school, “If it works, it must be a Fluke”