The Smell of Molten Projects in the Morning

Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.

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  • Multimeter Current-sense Resistor

    Replacing the battery in an old Craftsman (!) multimeter brought its 10 A current-sense resistor into the light:

    Multimeter current resistor - nipped copper wire
    Multimeter current resistor – nipped copper wire

    Unlike the contemporary AN8008/9 meters, it looks like an ordinary copper wire trimmed to the proper resistance by nipping it with a cutter.

    It measures something under 10 mΩ, so I’m sure they adjusted the resistance by applying a known current and watching the meter reading while crunching the wire until the proper value appears.

    I may have actually used the 10 A range, but I’d be hard pressed to say when or why, so the resistor is at least as good as it needs to be!