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What is the Alternating Current Symbol on a Multimeter?

31 July 2025 14500

 

 

Whether you're testing a wall outlet or troubleshooting an appliance, recognizing the AC symbol on your multimeter is crucial for getting accurate readings and staying safe. 

 

In this guide, we will explain what alternating current is, what the AC symbol looks like, where to find it on your multimeter, and how to use it properly. By the end, you’ll have a clear understanding of how to identify and apply AC settings with confidence.

 

 

What Is Alternating Current (AC)?​

 

What Is Alternating Current (AC)?​

 

Definition

Alternating current (AC) is a type of electrical current in which the flow of electrons periodically reverses direction. 

 

Direct current (DC) flows in a single, constant direction. AC alternates between positive and negative voltages in a wave-like pattern—most commonly a sine wave. 

 

The rate at which the current changes direction is measured in hertz (Hz), indicating cycles per second. For example, in many countries, the standard frequency is 50 Hz or 60 Hz.

 

How AC Differs from Direct Current (DC)?

 

How AC Differs from Direct Current (DC)?

 

  • AC (Alternating Current): Flow of electrons changes direction periodically. Voltage also alternates between positive and negative values.
  • DC (Direct Current): Flow of electrons is constant in one direction with steady voltage.

 

Therefore, AC is better suited for transmission over long distances and is used in most power distribution systems. DC, on the other hand, is commonly found in battery-powered devices and electronics.

 

Common Applications

  • Household electrical outlets (powering appliances, TVs, and lighting)
  • Power tools and machinery in workshops and factories
  • HVAC systems and large electrical motors
  • Public utilities like streetlights and subways

 

 

Alternating Current Symbol Basics

 

Standard Symbol: ~ or V~

 

Standard Symbol: ~ or V~

 

On a multimeter, the most common way to represent alternating current is with a tilde symbol (~). When measuring AC voltage, it typically appears as V~, meaning “volts alternating current.”

 

This setting is used when checking power outlets, appliances, and any other source delivering AC power.

 

Variations You Might See:

Different multimeters may display slightly different variations of the AC symbol. It depends on their design and manufacturer. Some common variations include:

  • A~: This means AC Current. The "A" stands for Amperes (Amps), the unit for measuring current.
  • mA~: This means milliamps AC (mA). A milliamp is one-thousandth of an Amp. This is used for measuring smaller AC currents safely.
  • BVAC–Volts AC, another way to indicate AC voltage
  • ACV / ACA–Common on older or budget models

 

These symbols serve the same purpose: to indicate the function for measuring alternating current in either volts, amps, or milliamps.

 

Explanation of the meaning of these symbols:

 

Explanation of the meaning of these symbols:

 

  • These symbols tell you which part of your multimeter’s functions is set to measure Alternating Current signals.
  • When you turn your dial to the V~ setting, you are ready to measure voltage from an AC source, like a wall outlet.
  • If you turn it to A~ or mA~, you are setting the multimeter to measure the flow (current) of AC electricity through a circuit.

 

How do the symbols differ between digital and analog multimeters?

 

Digital Multimeters: Almost always use the standard ~, V~, A~, or mA~ symbols. They are usually printed clearly on the dial near the selector switch. Functions are separated clearly.


Analog Multimeters (With Needles): These older style meters often share a scale on the display for different measurements. 

 

You might see a section of the dial labeled AC or V~, and you might also see a different section labeled DC. Be sure to look carefully at both the dial setting and the scale printed on the meter face.

 

 

Types and Meanings of AC Symbols

 

Multimeters may display various alternating current (AC) symbols, depending on the model, manufacturer, and measurement type. 

 

Understanding these symbols ensures correct usage and helps prevent errors during electrical testing. Below are the most common AC-related symbols and what they mean:

 

V~ (Volts AC)

 

V~ (Volts AC)

 

  • Meaning: Measures AC voltage
  • Use: Testing wall outlets, appliance outputs, or any AC power source
  • Example: A standard 120V or 230V outlet

 

A~ (Amps AC)

 

A~ (Amps AC)

 

  • Meaning: Measures AC current
  • Use: Checking current draw in AC circuits like motors, heaters, or large appliances
  • Note: Often requires special multimeter functions or clamp attachments

 

mA~ (Milliamps AC)

  • Meaning: Measures small AC currents
  • Use: Useful for precise, low-power AC applications, such as signal testing or sensitive circuits

 

VAC / ACA

  • VAC: Volts Alternating Current
  • ACA: Amps Alternating Current
  • Use: Found on some multimeters in place of symbols like V~ or A~

 

~ Only (Standalone Tilde)

  • Meaning: Indicates AC mode (voltage or current), usually when used alongside a range selector or unit label
  • Common in: Simpler or analog multimeters

 

Combined Symbols (V/ V~ / V⎓ / V⎓~)

Some multimeters combine AC and DC symbols in one setting or label. For example:

  • V⎓~ or V AC/DC means the multimeter can auto-detect or manually select AC or DC voltage
  • Dual markings may require toggling between modes with a button

 

Quick Reference Table

Symbol Meaning Used For
V~ AC Voltage Wall outlets, appliances
A~ AC Current High-power devices, circuits
mA~ AC Milliamps Low-current AC systems
VAC Volts Alternating Current Same as V~, just spelled out
ACA Amps Alternating Current Same as A~, just spelled out
~ General AC indicator Context-dependent (voltage or current)

 

 

Where to Find the AC Symbol on a Multimeter?​

 

Accurately identifying the AC setting on a multimeter is crucial for safely measuring household electricity and other AC-powered circuits. While multimeters may differ slightly in layout and labeling, most follow a common pattern.

 

Typical Multimeter Dial Layout

 

Most multimeters—especially digital models—feature a rotary dial in the center. Users can select different measurement modes. The dial is usually divided into sections labeled for:

 

Typical Multimeter Dial Layout

 

Within the voltage and current sections, you’ll typically find separate options for AC and DC:

  • AC Voltage: Often labeled V~
  • AC Current: Labeled A~ or mA~, depending on the range

 

These settings might be grouped together with their DC counterparts or placed in separate segments of the dial.

 

How to Find the AC Setting on Common Multimeter Types?

 

Digital Multimeters (DMMs):

 

Digital Multimeters (DMMs):

 

  • AC voltage: V~, VAC, or sometimes a wave (~) symbol next to a "V"
  • AC current: A~, mA~, or ACA
  • These are typically shown on the dial or screen with clear digital readouts

 

Analog Multimeters:

 

Analog Multimeters:

 

  • AC voltage and current ranges may be marked in colored bands
  • The dial may simply show "AC" near voltage or current ranges, or a standalone ~ symbol

 

Auto-ranging Multimeters:

 

Auto-ranging Multimeters:

 

Often combine AC/DC functions. It requires the user to press a “Mode” or “Select” button to switch between AC and DC once the dial is set to voltage or current.

 

What to do if your multimeter uses icons instead of letters?

 

What to do if your multimeter uses icons instead of letters?

 

Some modern or compact multimeters use icons instead of written labels. If you don’t see V~, A~, or "AC", look for:

  • A tilde (~) symbol – usually indicates alternating current
  • A wave-like line (representing an AC sine wave)
  • Dual symbols like V⎓/~ or a button labeled “Mode”, meaning the multimeter can switch between AC and DC

 

If you’re unsure what a symbol means:

  • Check the user manual–most manuals include a legend for all dial positions.
  • Look online for your model's dial guide–manufacturers often provide labeled diagrams.
  • Use caution–never assume a symbol’s meaning if you’re dealing with live circuits.

 

 

Application of AC Symbols

 

Application of AC Symbols

 

Understanding and correctly using AC symbols on a multimeter is essential for performing accurate electrical measurements, especially when dealing with alternating current systems. 

 

These symbols guide users in selecting the appropriate settings for various tasks. Below are common applications where AC symbols play a critical role:

 

Measuring Household AC Voltage

  • Symbol Used: V~ or VAC
  • Application: Checking the voltage of wall outlets or power strips (typically 120V or 230V, depending on your country).
  • Purpose: Ensures the outlet is supplying the correct voltage for appliances or troubleshooting power issues.

 

Testing AC Current in Appliances

  • Symbol Used: A~ or ACA
  • Application: Measuring current draw of devices like microwaves, heaters, or motors.
  • Purpose: Useful for diagnosing electrical load, energy consumption, or circuit overloads.

 

Verifying Power Tool Output

  • Symbol Used: V~, A~
  • Application: Confirming voltage or current levels delivered to tools such as drills, saws, or welders.
  • Purpose: Ensures tools are operating within safe and expected parameters.

 

Troubleshooting Circuit Breakers or Power Panels

  • Symbol Used: V~
  • Application: Measuring voltage across breakers or fuses.
  • Purpose: Helps detect power loss, identify faulty breakers, or confirm proper operation.

 

Monitoring AC Signals in HVAC or Industrial Equipment

  • Symbols Used: V~, mA~
  • Application: Checking signal voltages in thermostats, control panels, or industrial sensors.
  • Purpose: Verifies control voltage levels and system responsiveness.

 

Testing Transformers or Power Supplies

  • Symbols Used: V~, A~
  • Application: Verifying input/output voltage and current on transformers or AC adapters.
  • Purpose: Ensures correct step-up or step-down function and detects malfunctioning components.

 

 

How to Use the AC Setting on a Multimeter?

 

 

Step-by-step guide to measuring AC voltage

 

1.Turn the Dial to AC Voltage (V~)

  • Locate the V~ or VAC setting on your multimeter's dial.
  • If your multimeter shares AC and DC under the same setting, press the “Mode” or “Select” button to toggle to AC.

 

2.Plug in the Test Leads

  • Black lead into the COM (common) port.
  • Red lead into the VΩmA port (sometimes just labeled "V" on basic meters).

 

3.Verify the Range (Manual Multimeters Only)

If your multimeter is not auto-ranging, select a voltage range higher than the expected value (e.g., 250V for testing a 120V outlet).

 

4.Take the Measurement

  • Insert the probes into the live and neutral slots of the outlet or touch them to the two points in the AC circuit.
  • Read the value displayed on the screen.

 

5.Interpret the Reading

A normal household outlet should show a voltage close to 110–120V (North America) or 220–240V (many other countries).

 

Example: Testing a Wall Outlet

 

 

Tools Needed:

  • Digital multimeter
  • Insulated test leads

 

Steps:

  • Set your multimeter to V~.
  • Insert the black probe into the neutral slot (usually the larger vertical slot).
  • Insert the red probe into the hot slot (smaller vertical slot).
  • Observe the reading. It should be within the standard household voltage range (e.g., ~120V in the U.S.).
  • To test the ground, move the black probe to the ground slot (round or U-shaped), keeping the red probe in the hot slot. A normal reading here also indicates a properly grounded outlet.

 

Safety Precautions When Working with AC

  • Never measure AC with the multimeter set to DC or resistance—doing so can damage the meter or cause injury.
  • Always start with the highest range on manual meters to prevent overload.
  • Use only insulated test probes rated for the voltage you're measuring.
  • Keep fingers behind the probe guards to avoid accidental contact with live wires.
  • Do not touch both probes at once or make contact with the metal tips while measuring.
  • Avoid measuring live circuits in wet or damp environments.
  • Inspect test leads and multimeter body for cracks or exposed wires before use.

 

 

AC and DC Symbols On A Multimeter

 

AC and DC Symbols On A Multimeter

 

In the article "What is the DC Voltage Symbol on a Multimeter?", we learned the symbol for DC voltage. Now let's understand the difference between AC (Alternating Current) and DC (Direct Current) symbols.

 

Tip

Rule of Thumb:If you’re testing a wall outlet or appliance, use AC (V~); If you’re testing a battery or low-voltage circuit, use DC (V⎓ or V–).

 

The Basic Symbols

Type Common Symbols on Multimeters Meaning
AC ~, V~, A~, mA~, VAC, ACA Alternating Current – the current changes direction periodically
DC ⎓, V⎓, A⎓, mA⎓, V–, VDC, ADC Direct Current – current flows in one constant direction
  • Tilde (~): Represents AC, often used with letters like V~ (volts) or A~ (amps)
  • Straight line with dashed line below (⎓): Represents DC; sometimes replaced by a minus sign (–)

 

Visual Representation

  • AC Symbol (V~): Often shown as a wave or tilde (~). This reflects the oscillating nature of alternating current.
  • DC Symbol (V⎓ or V–): Depicted as a straight line over a dashed line, indicating a steady, unidirectional flow.

 

Functional Differences

Feature AC DC
Voltage Symbol V~ V⎓ or V–
Current Symbol A~ A⎓ or A–
Typical Applications Wall outlets, appliances, power tools Batteries, electronics, car circuits
Multimeter Setting Used for mains voltage or AC signals Used for battery or circuit testing

 

Choosing the wrong symbol or setting can result in:

  • Incorrect readings (showing zero or unstable values).
  • Internal fuse blowouts in the multimeter (especially when measuring current).
  • Safety risks, particularly when working with high-voltage AC systems.

 

 

Common Misunderstandings​

 

Common Misunderstandings​

 

When using a multimeter to measure alternating current (AC), it’s easy to make mistakes—especially for beginners. 

 

Misunderstanding the symbols, functions, or settings can lead to inaccurate readings, damaged equipment, or even personal injury. Below are some of the most common errors and misconceptions related to AC measurements:

 

Confusing AC and DC Symbols

  • Many users mistake V~ (AC voltage) for V⎓ or V– (DC voltage).
  • Choosing the wrong setting may result in a “0” reading, unstable values, or incorrect diagnostics.

 

Using the Wrong Ports for AC Current

  • Measuring AC current (A~) usually requires moving the red test lead to a separate current input port (often marked 10A or A).
  • Plugging the leads into the voltage ports while on a current setting can blow the internal fuse or damage the multimeter.

 

Expecting AC Voltage on Battery-Powered Devices

  • Batteries and most electronics output DC, not AC.
  • Trying to measure battery voltage using the AC setting will result in incorrect or near-zero readings.

 

Assuming All Multimeters Auto-Detect AC/DC

 

Assuming All Multimeters Auto-Detect AC/DC

 

  • Some users think the multimeter will automatically detect AC or DC—this is only true for auto-sensing models.
  • Manual meters require you to manually select the correct mode; using the wrong one can confuse readings or harm the meter.

 

Misreading the Display Units

Misinterpreting readings (e.g., assuming millivolts are volts) due to not noticing the unit prefix (mV~, V~, etc.) on the screen.

 

Measuring Current Like Voltage

  • Current must be measured in series, not across a component.
  • Attempting to measure AC current the same way as voltage (in parallel) can short the circuit or trip breakers.

 

Overlooking Safety Ratings

Ignoring CAT ratings (e.g., CAT II, CAT III) and using a multimeter outside its safe voltage range when measuring mains AC can result in electrical hazards.

 


By understanding what AC is (electricity that constantly changes direction), recognizing its standard symbol (~), and knowing where to find it on your multimeter (usually in the V~ or ACV section), you gain a fundamental tool for safe electrical testing.

 

 

Frequently Asked Questions

What is the symbol for alternating current?

The symbol for alternating current is a wavy line (~) or the abbreviation "AC".

Is home electricity AC or DC?

Home electricity is typically alternating current (AC). Because it is more efficient for long-distance transmission.​

How to tell if it is AC or DC?

You can use a multimeter to measure the voltage and observe the direction of current flow. AC voltage alternates direction periodically, often shown by a wavy line on meters. While DC voltage remains constant, typically indicated by a straight line.

How to use a multimeter for AC current?

To measure AC current with a multimeter, set it to the AC current (A with a wave symbol) setting, choose an appropriate range. And connect it in series with the circuit, and turn on the circuit. Finally, read the value displayed on the multimeter's screen. 

What happens if you use AC instead of DC?

Using AC instead of DC in a DC-designed device can potentially cause  overheating, short circuits, or even fire. 

Why is alternating current better?

Alternating current (AC) is the dominant electrical power system. Because it can be easily transformed to higher or lower voltages using transformers, reducing energy loss.

What can an alternating current Cannot be used for?

Alternating current (AC) cannot be directly used in devices requiring steady, unidirectional current, such as battery charging or electroplating. It's also not ideal for devices that rely on the precise direction of current flow in their operation.

What household appliances use alternating current?

Household appliances like refrigerators, air conditioners, washing machines, TVs, and electric water heaters typically use alternating current (AC) for direct operation.

 

 

Read  More:

The Ultimate Guide to Multimeter Symbols and How to Use Them

 

Extended More:

A Compete Guide to AC Capacitor Wiring Colors

Alkaline vs Carbon Batteries Key Differences You Should Know

Temperature Sensors Types, How They Work & Applications

21700 battery vs 18650 A Comparison Guide

RJ45 Color Code | T568A vs.T568B Which Should You Use?

 

 

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Anderson Snape
Anderson Snape, born in 1972, completed his undergraduate studies at Loughborough University in the UK in 1993 and received a bachelor's degree in electrical engineering. In 1996, he furthered his studies and obtained a master's degree from Newcastle University. As a senior engineer in the field of integrated circuit testing, Anderson has been working in the chip testing industry for more than 20 years, accumulating profound professional experience and holding unique insights into the industry. He not only focuses on technical practice, but also actively engages in chip-related science popularization work. At the same time, he keeps up with the current hot topics in the semiconductor industry and has made important contributions to the progress and development of the industry.
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