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Multimeter Questions about damage.

  1. Oct 2, 2012 #1
    Is it possible to damage the continuity tester if the leads are hooked to a battery?

    For a clamp on AC amp meter; Is it possible to damage the sensor if put around a DC hot wire in a circuit?

    I am so surprised it is difficult to find events of people damaging their meters. God knows the instructions mention little about how to damage them.

    Thanks for your support.
     
  2. jcsd
  3. Oct 2, 2012 #2

    davenn

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    Hi Flyingwing :)

    Probably ... Yes as the tester is lupplying just a small current through its probas and the circuit under test .... It is doubtful that it could handle an excessive voltage/current source being applied

    I will go with no... as it is an AC detector, there is probably capacitive coupling in there and that will stop any DC currect from flowing

    Well there has been many a multimeter damaged through being connectedto a power source when the meter has been in the incorrect range setting.

    Dave
     
  4. Oct 3, 2012 #3

    es1

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    Multimeter's themselves are pretty robust beasts. But I can say with certainty that is due to the fuses within them. I've replaced a good number of fuses in the Fluke over the years. Every "damaged" DMM I've ever seen was recovered by a fuse change.
     
  5. Oct 3, 2012 #4

    AlephZero

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    I agree digital meters are harder to kill than the old analog ones. If nothing else, a display that can show a "-" sign does less damage than bending the pointer of an analog meter by connecting it the wrong way round.

    But blowing up a meter is one of the rites of passage in practical electronics. Most people have done it, but they don't talk about it much. It also explains why people who own a meter costing $1000 usually also have several "expeodable" $10 ones.
     
  6. Oct 5, 2012 #5

    jim hardy

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    ammeter connected to a voltage source will pass however much current the source is capable of delivering, and that's why they are fused.
    Fluke has a good tutorial on why to use the correct fuse - wrong fuse can allow quite an explosion and fireball.

    Analog Ohmmeter on RX1 is low resistance and it is not uncommon to burn up the range resistor by connecting to volts while RX1 is selected. Symptom is it only reads 0 ohms. If that happens, you'll see it burnt and charred maybe exploded on the board. Fortunately it has same value as midscale on RX1 meter scale so you know what value to replace it with.

    everybody wrecks one.

    A huge DC through an AC clamp-on can leave the core permanently magnetized which gives erroneous reading. Fix is easy - measure a large ac current with it.
     
  7. Oct 5, 2012 #6

    A good way to test for correct AC is to split the wires going to a lamp, and use the V/I=R to confirm the reading.

    This cheapy harbor freight deal works amazingly well.

    By the way, for anybody who hasn't thought of it yet, I have included a diagram of a neat little fixture that I use to measure current without splitting wires.

    pretty basic ideas, but I have never seen them for sale. (insert 1950's idea here)
     

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