What Is a Milliammeter?

What Is a Milliammeter?

ByKen

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A milliammeter is a meter, or a meter setting, that measures electric current in milliamps (mA). Fluke’s guide to multimeter dials and buttons lists “mA, μA (milliamps, microamps)” as current measurement settings, with a range of “0 μA to 400 mA (up to 600 mA for 18 hours).” The milliamp setting is for small currents. For larger currents, the listing or manual for your meter will show a different range.

Quick answer

  • A milliammeter measures current in milliamps (mA), usually as a setting on a digital multimeter.
  • Fluke gives one range as 0 μA to 400 mA, with 600 mA allowed for up to 18 hours.
  • Not every meter has a separate input jack for milliamp measurements. Check the jacks on your meter before you connect the leads.
  • Current measurement needs a working fuse. Use the fuse rating from the manual and confirm the fuse is good before you measure.

What the milliamp setting covers

The Fluke dial guide gives the current range as “0 μA to 400 mA (up to 600 mA for 18 hours).” Compare the current you expect with that range before you measure, as the next section explains. The same guide notes that “Not all meters offer an input jack for milliamps,” so the lead position depends on the model.

Fuses and input jacks

Fluke’s fuse article explains that voltage inputs are usually protected against overvoltage rather than fused. It adds that “if that same tester is designed to also measure current, fusing is required.” The manufacturer lists the amperage, interrupt and voltage ratings for replacement fuses in the manual and often on the meter itself. The article warns that a fuse with the wrong rating, or a wire wrapped around the fuse connections, can turn a fault into a dangerous event.

Before you measure current

Fluke’s current measurement guide gives three checks. First, “Determine the circuit’s anticipated maximum current by checking the nameplate of a component or the breaker rating.” Second, confirm that the range of your multimeter or clamp accessory is high enough for that current. If it is not, the guide says to “select an instrument equipped for higher ranges.” Third, “If a meter includes fused current terminals, verify that its fuses are good.”

Safety

Work on mains circuits can kill. The meter’s CAT rating must suit the circuit you are testing, and panel or service work belongs to a licensed electrician. The sources we opened do not give a CAT rating for any specific meter, so check the manual for your model.

How we chose

This post covers one term. We used the three Fluke pages listed under Sources because each one describes a part of the milliamp setting: the setting and its range, the input jack, and the fuse requirement. We did not compare meter models for this post.

What we could not verify

The sources we opened do not list the milliamp range or the fuse ratings for any specific meter model. Those figures have to come from the manual or the product listing for your meter.

FAQ

Does every multimeter have a milliamp setting?

The Fluke dial guide lists milliamp and microamp current settings, but it also notes that “Not all meters offer an input jack for milliamps.” Check the setting and the jack on your own meter.

Does a current setting need a fuse?

Yes, according to Fluke’s fuse article. If a tester is designed to measure current, “fusing is required.” Check that the fuse is the rating the manual specifies.

How do I know what current to expect?

Fluke’s current guide says to start with the circuit’s anticipated maximum current, found on “the nameplate of a component or the breaker rating.” Compare that figure with your meter’s range.

Can a milliammeter be used on mains circuits?

Mains work can kill. The sources we opened do not state a CAT rating for any meter, so confirm the rating in your manual and leave panel work to a licensed electrician.

Bottom line

A milliamp setting measures small currents in milliamps. Before you connect a meter to a circuit, confirm the range, the input jack and the fuse rating on that meter.

Related guides

Sources

  • Fluke, “The Dials, Buttons, Symbols, and Display of a Digital Multimeter,” https://www.fluke.com/en-us/learn/blog/digital-multimeters/multimeter-dial-button-jacks-display (opened 2026-10-27)
  • Fluke, “How to Choose the Correct Fuse for Your Tester,” https://www.fluke.com/en-us/learn/blog/digital-multimeters/choosing-the-correct-fuse-for-your-tester (opened 2026-10-27)
  • Fluke, “How to Measure Current with a Clamp Accessory,” https://www.fluke.com/en-us/learn/blog/digital-multimeters/how-to-measure-current-with-clamp-accessory (opened 2026-10-27)

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