SESKStuff Everyone Should Know
SESK: Stuff Everyone Should Know · sesk.info/elec-meter-a-input-short

What happens if you measure voltage with the leads plugged into the A or mA inputs?

It makes a short circuit through the meter.

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  1. The reading is simply half
  2. You create a short in the measurement circuit ✔
  3. Nothing, the meter autoranges

Why: Current inputs have almost no resistance so current can pass through the meter. Across a voltage source that makes a near short, which can blow the meter's fuse or worse.

Huh, didn't know that: Fluke also warns not to let fingers touch the lead tips.

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My extension lead just ran away, it needed more outlets.
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References

Answer: You create a short in the measurement circuit. Current inputs have almost no resistance so current can pass through the meter. Across a voltage source that makes a near short, which can blow the meter's fuse or worse.

  1. Fluke: How to Measure AC Voltage with a Digital Multimeter www.fluke.com/en-us/learn/blog/digital-multimeters/how-to-measure-ac-voltage-with-a-digital-multimeter
    Placing test leads in A or MA inputs and then measuring voltage will create a short in the measurement circuit.
    Checked 2026-10-10.

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