Reference · updated 10 November 2026
Multimeter symbols: what each one means
A multimeter packs a lot of meaning into small symbols: a V with a straight line is DC voltage, a V with a wavy line is AC voltage, and the multimeter continuity symbol is a sound wave. This page lists each symbol on a dial or display with a drawing and a one-line meaning. The drawings are simplified; your meter may print a slightly different version, but the idea is the same.
iPhone and iPad (iOS 17 or later): free on the App Store. Android later.
Voltage and current symbols
The straight line with dashes is direct current (DC); the wavy line is alternating current (AC). The letter says what is measured: V for volts, A for amps.
| Symbol | Name | What it means |
|---|---|---|
| DC voltage (V with straight and dashed line) | Direct-voltage measurement: batteries, power supplies, car and electronics circuits. | |
| AC voltage (V with wavy line) | Alternating-voltage measurement, such as mains outlets and transformers. | |
| AC+DC voltage | Reads the AC and DC parts together, used for signals with both. | |
| Millivolts (mV) | Small DC voltages, such as sensor and thermocouple signals and voltage drops. | |
| DC current (A with straight line) | Direct current in amps, measured with the meter in series with the load. | |
| AC current (A with wavy line) | Alternating current in amps, also measured in series. |
Multimeter continuity symbol
The continuity symbol is a speaker with sound waves coming out of it. It is the setting that makes the meter beep when two points are connected by a low-resistance path, so you can test a wire, a switch or a fuse without looking at the display. On many meters it shares a dial position with ohms and the diode symbol; a button (SELECT, FUNC or the blue key) cycles between them. When the symbol shows in the display, the meter is in continuity mode.
A beep means the resistance between the probes is below a threshold, often somewhere between 10 Ω and 50 Ω (check your manual); silence and OL mean an open path. The circuit must be off and isolated for the test. For the full procedure and the usual mistakes, read how to test continuity with a multimeter.
Resistance, diode, capacitance and other functions
Most of these positions share the dial or a function button, so a symbol only appears when you have selected it.
| Symbol | Name | What it means |
|---|---|---|
| Resistance (Ω) | Measures resistance in ohms. The circuit must be off; see the resistor color code chart for reading the value of a resistor. | |
| Diode test (triangle and bar) | Shows the forward voltage drop of a diode or LED junction; a good silicon diode reads about 0.5 to 0.7 V one way and OL the other. | |
| Capacitance (two plates) | Measures capacitance in nF, µF or mF. Discharge the capacitor first; see how to test a capacitor with a multimeter. | |
| Frequency (Hz) | Counts how many cycles per second a signal has. | |
| Duty cycle (%) | The share of each cycle a square-wave signal is high, in percent. | |
| Temperature (°C / °F) | Reads temperature with a thermocouple probe, usually type K. | |
| Transistor hFE | Socket for testing the gain of a small bipolar transistor. | |
| NCV | Non-contact voltage: detects mains voltage near a wire without touching metal. Use it as an indication only and confirm with a real measurement. |
Display and button symbols
These show a mode the meter is in. They appear in the display, and many are also printed next to a button.
| Symbol | Name | What it means |
|---|---|---|
| HOLD | Freezes the displayed value so you can read it after taking the probes away. | |
| RANGE / AUTO | Switches between auto-range and a fixed range. AUTO in the display means the meter picks the range. | |
| REL (Δ) | Relative mode: shows the difference from a stored reference, for example to subtract the test-lead resistance. | |
| MAX / MIN | Keeps the highest and lowest reading since you pressed it. | |
| Backlight | Turns the display light on, usually with a long press on a button. | |
| Low battery | The battery is nearly flat; readings may become unreliable, so replace it. |
Fuse, CAT ratings and input jacks
These tell you what the meter can safely handle and where the leads go.
| Symbol | Name | What it means |
|---|---|---|
| Fuse | The current inputs are protected by a fuse. A blown fuse stops current readings; see how to test a fuse with a multimeter. | |
| CAT II / III / IV with a voltage | Measurement category and maximum voltage for the meter. A higher category is for a place closer to the supply, with larger surges; use a meter rated for the place you measure. | |
| COM jack | Common jack: the black probe goes here for every measurement. | |
| V-ohm jack (VΩ) | The red probe goes here for voltage, resistance, continuity, diode, capacitance and frequency. | |
| mA jack (µA, mA) | The red probe goes here for small currents, through a fuse. | |
| 10 A jack | The red probe goes here for large currents, up to the rated amps for a short time. |
Read this live with a meter
The app reads a Bluetooth multimeter such as the OWON OW18B live and shows the value with its unit. A reading of OL is shown as OL, never as a number. The app's HOLD freezes the displayed reading and its statistics, independent of the meter's own HOLD, it shows the running minimum, maximum and average, and REL shows the difference from a stored reference; see Hold, REL and Min/Max.
The calculator in the app has preset formulas for Ohm's law and power, series and parallel, dividers, LED resistors, RC, dB and unit conversion, and Cal Box fills it from your live reading and recent captures. The app does not explain symbols on the meter itself; this page is the reference.
What the app does here, and what it doesn't
| What it does | Plan |
|---|---|
| A large readout that shows which digits have settled; OL and UL are shown as OL and UL, never as a number. | Free |
| Hold freezes the displayed reading and statistics in the app, independent of the meter's own HOLD. | Free |
| Shows the running minimum, maximum and average since the last reset, with the sample count. | Free |
| REL shows the difference from a stored reference, for example to null out test-lead resistance. | Free |
| Presets for Ohm's law and power, series and parallel, dividers, LED resistors, RC, dB and unit conversion. | Free |
| Cal Box fills the calculator from your live reading and recent captures, and suggests Ohm's law. | Free |
Questions
What is the multimeter continuity symbol?
It looks like a sound wave or a speaker with waves coming out of it. Turn the dial to it and the meter beeps when two points are connected. It often shares a position with ohms and the diode symbol, and a button switches between them.
What does the symbol with a straight line and a dashed line mean?
It is direct current (DC). In front of a V it is DC voltage, in front of an A it is DC current. The wavy line (~) means alternating current (AC).
What is the difference between the continuity and diode symbols?
Continuity beeps when the resistance is low and tells you a path exists. The diode test applies a small current and shows the forward voltage drop in volts. They are often next to each other on the dial.
What do CAT II, CAT III and CAT IV mean on a multimeter?
They are measurement categories for overvoltage: the higher the number, the closer to the supply and the larger the possible surge. The voltage printed next to it is the maximum for that category. Use a meter rated for the place where you measure.
Which jack does the red probe go in?
Black always goes in COM. Red goes in the V-ohm jack for voltage and resistance, in the mA jack for small currents and in the 10 A jack for large currents. Move the lead back to V-ohm after a current measurement.
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