what does this symbol mean?

Multimeter symbols

What the symbols on a multimeter’s dial, jacks and display mean, from V and Ω to the continuity beeper, CAT ratings and OL.

Test yourself: Multimeter symbols quiz

Dial settings 10 symbols

Jacks and ratings 3 symbols

Display 4 symbols

About multimeter symbols

A multimeter’s dial, jacks and display share a small set of symbols, and most meters use the same ones. The letter says what is measured: V for volts, A for amps, Ω for ohms, F for farads and Hz for hertz. The mark beside it says what kind: a solid line over three dashes (⎓) is direct current and a wave (∿) is alternating current, so V⎓ is DC volts and V~ AC volts. These pages describe what each symbol means, from Fluke’s, Klein Tools’, Extech’s and Mastech’s manuals; the meter’s own manual says how to use it.

The dial

Besides volts, amps and ohms, most dials have a continuity setting, drawn as a dot with sound waves, that beeps on a low resistance, and a diode test, drawn as the diode’s circuit symbol. Many add capacitance, frequency and temperature, and some a transistor socket marked hFE. Fluke prints secondary functions in yellow and Klein in orange, chosen with a function or SEL button.

The jacks and the case

The black lead goes in COM, the common jack, for every measurement. Current has its own jacks, marked with their limit and the word FUSED, such as 10A. Near the jacks is the CAT rating: CAT II, III or IV with a voltage, the measurement category from the safety standard IEC 61010-1. A higher CAT number means the meter is built for higher-energy voltage spikes, closer to the utility supply.

The display

OL means the reading is too large for the range; on resistance and continuity it means an open circuit. HOLD freezes the reading, AUTO means the meter picks its own range, and a battery icon means the meter’s battery is low. The thresholds and ranges behind each symbol differ between makers: Fluke’s 117 beeps for continuity below 20 Ω, Klein’s MM400 below 50 Ω and Extech’s EX330 below about 100 Ω.

Sources

  1. Multimeter Symbols, Buttons, Dials, and Display, Fluke learning centre article, Fluke Corporation, Dial, buttons, jacks and display
  2. MM400 Auto-Ranging Digital Multimeter: Instruction Manual, MM400 instruction manual, Klein Tools (copy hosted by UBC Earth, Ocean and Atmospheric Sciences), Symbols on meter; Symbols on LCD; Electrical specifications; Function buttons
  3. Mini Multimeter with Non-Contact Voltage Detector, Model EX330: User’s Guide, EX330-EU-ENG V4.2 1/08, Extech Instruments (copy hosted by Core Electronics), Display symbols; General specifications
  4. 114, 115, and 117 True-rms Multimeters: Users Manual, PN 2572573, July 2006, Rev. 1, 2/07, Fluke Corporation (copy hosted by UCL Electronic and Electrical Engineering), Introduction; Rotary switch positions; Display
  5. ABCs of multimeter safety, Application note, Fluke Digital Library, Fluke Corporation (copy hosted by RS Components), Measurement categories
  6. MAS838 Digital Multimeter: Operator’s Instruction Manual, MAS838 manual, Mastech (copy hosted by Akizuki Denshi), Specifications

Researched, edited and approved by Rory Hansen before publishing. Last reviewed October 9, 2026. How we research