Ammeter symbol

A circle containing a capital A, measuring current.

Also known as: Current meter symbol, Milliammeter symbol

Engineering & technicalStandard profile

Meanings

A measuring instrument is drawn as a circle containing the letter for the quantity it measures. An ammeter goes in series with the circuit, which is the practical fact: connected across a supply instead, a low-resistance ammeter is a short circuit.

Officially standardisedVerified fact
Denotes an instrument measuring electric current, drawn as a circle enclosing a capital A.
Contexts: Technical drawing, Electrical equipment
Officially standardisedVerified fact
Is connected in series with the circuit under test, because its resistance is deliberately low and placing it across a supply would short it.
Contexts: Technical drawing, Electrical equipment

Visual description

A circle enclosing a single capital letter, with two connections leaving opposite sides.

Symmetry: radial
Orientation: upright

Confidence

IdentityHigh confidence: High confidence because the identity is documented in encyclopedic references, but multiple independent sources agree.
Historical originModerate confidence: Moderate confidence because the historical origin is documented in encyclopedic references, but multiple independent sources agree, but early or supporting evidence is limited, but the regional or cultural match to this specific claim is not precise.
Current useHigh confidence: High confidence because the current use is documented in encyclopedic references, but multiple independent sources agree.
Visual matchHigh confidence: High confidence because the visual match is documented in encyclopedic references, but multiple independent sources agree.

Sources

ANSI Y32.2 / IEEE 315, Graphic Symbols for Electrical and Electronics Diagrams
IEEE / American National Standards Institute · retrieved 2026-08-22
Paywalled and NOT READ in full. Registered so the zig-zag resistor familiar from American schematics can be attributed to the standard that defines it, rather than described as the 'old' or 'wrong' form. See docs/paywalled-standards.md.
Electronic symbol
Wikipedia · retrieved 2026-07-31
Tertiary reference. Used for what the component is, how its symbol is conventionally drawn, and where the ANSI and IEC conventions differ. Not used for any claim about the text of IEC 60617, which is paywalled and was not consulted.
IEC 60617, Graphical symbols for diagrams
International Electrotechnical Commission · retrieved 2026-08-22
Maintained as an online database and NOT READ in full. Registered so a circuit-diagram record can say which body defines its symbol, and so the divergence between the IEC form and the older American form can be recorded as a real standards difference rather than a drawing preference. See docs/paywalled-standards.md.
Circuit diagram
Wikipedia · retrieved 2026-07-31
Tertiary reference. Used for what the component is, how its symbol is conventionally drawn, and where the ANSI and IEC conventions differ. Not used for any claim about the text of IEC 60617, which is paywalled and was not consulted.

Last reviewed 2026-08-23

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Circuit and electronic symbols

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Meanings

Officially standardisedVerified fact

Denotes an instrument measuring electric current, drawn as a circle enclosing a capital A.

Contexts: Technical drawing, Electrical equipment

Officially standardisedVerified fact

Is connected in series with the circuit under test, because its resistance is deliberately low and placing it across a supply would short it.

Contexts: Technical drawing, Electrical equipment

Confidence

IdentityHigh confidence: High confidence because the identity is documented in encyclopedic references, but multiple independent sources agree.
Historical originModerate confidence: Moderate confidence because the historical origin is documented in encyclopedic references, but multiple independent sources agree, but early or supporting evidence is limited, but the regional or cultural match to this specific claim is not precise.
Current useHigh confidence: High confidence because the current use is documented in encyclopedic references, but multiple independent sources agree.
Visual matchHigh confidence: High confidence because the visual match is documented in encyclopedic references, but multiple independent sources agree.

Sources

ANSI Y32.2 / IEEE 315, Graphic Symbols for Electrical and Electronics Diagrams
IEEE / American National Standards Institute · retrieved 2026-08-22
Paywalled and NOT READ in full. Registered so the zig-zag resistor familiar from American schematics can be attributed to the standard that defines it, rather than described as the 'old' or 'wrong' form. See docs/paywalled-standards.md.
Electronic symbol
Wikipedia · retrieved 2026-07-31
Tertiary reference. Used for what the component is, how its symbol is conventionally drawn, and where the ANSI and IEC conventions differ. Not used for any claim about the text of IEC 60617, which is paywalled and was not consulted.
IEC 60617, Graphical symbols for diagrams
International Electrotechnical Commission · retrieved 2026-08-22
Maintained as an online database and NOT READ in full. Registered so a circuit-diagram record can say which body defines its symbol, and so the divergence between the IEC form and the older American form can be recorded as a real standards difference rather than a drawing preference. See docs/paywalled-standards.md.
Circuit diagram
Wikipedia · retrieved 2026-07-31
Tertiary reference. Used for what the component is, how its symbol is conventionally drawn, and where the ANSI and IEC conventions differ. Not used for any claim about the text of IEC 60617, which is paywalled and was not consulted.

Last reviewed 2026-08-23