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Electronic Symbols Reference

Quick reference of common component schematic symbols + ANSI / IEC comparison.

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What it does: Look up what the schematic symbols for common circuit components look like and the ANSI vs IEC drawing differences.

When to use it: When reading schematics, drawing circuits, or identifying unfamiliar symbols.

16 common schematic symbols? in total, searchable or filterable by category.

Resistor
Limits current and divides voltage; unit Ω.
ANSIANSI zigzag IECIEC rectangle
Potentiometer
Adjustable resistor, three terminals, often used for voltage dividing / adjustment.
ANSIResistor + arrow wiper IECRectangle + arrow
Capacitor
Stores charge, blocks DC and passes AC; unit F.
ANSITwo parallel lines IECTwo parallel lines
Polarized Cap
Electrolytic/tantalum capacitor; has positive and negative terminals and is easily damaged if connected backwards.
ANSIOne straight + one curved line + polarity IECSolid + hollow
Inductor
Stores magnetic energy, resists AC; unit H.
ANSIContinuous semicircle coil IECRectangle or coil
Diode
Conducts in one direction; arrow points in the forward direction (anode → cathode).
ANSITriangle + bar IECSame as ANSI
LED
A diode that emits light when forward-biased; needs a series current-limiting resistor.
ANSIDiode + two arrows IECSame as ANSI
Zener Diode
Regulates voltage via reverse breakdown; used for references / clamping.
ANSIDiode + bent bar IECSame as ANSI
NPN Transistor
Bipolar junction transistor; emitter arrow points outward.
ANSIArrow points outward (emitter) IECSame as ANSI
PNP Transistor
Bipolar junction transistor; emitter arrow points inward.
ANSIArrow points inward (emitter) IECSame as ANSI
Ground
Potential reference point (0V).
ANSIThree decreasing horizontal lines IECSame as ANSI
Battery
DC power source; the long line is the positive terminal.
ANSIAlternating long and short lines IECSame as ANSI
DC Source
Ideal DC voltage/current source.
ANSICircle + ＋/－ IECCircle with a straight line
AC Source
Ideal AC voltage source.
ANSICircle + sine wave IECSame as ANSI
Switch (SPST)
Single-pole single-throw; opens and closes a circuit.
ANSIOpen lever IECSame as ANSI
Fuse
Blows on overcurrent to protect the circuit.
ANSIRectangle / with a horizontal line IECRectangle

MEANS You can match any symbol you do not recognize here; for components with a direction (diodes, transistors, polarized capacitors), be sure to connect them per the arrow/polarity.

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How to

How to use the electronic symbols reference

Search/filter → compare the symbol → mind the orientation.

  1. 01

    Search or filter

    Type a component name in the search box, or click a category tag to narrow the list.

  2. 02

    Compare symbol and notes

    Each card shows the symbol, name, and use, along with the difference between the ANSI (US) and IEC (European/international) drawing styles.

  3. 03

    Mind the orientation

    Diodes, transistors, and polarized capacitors have a direction; drawing them backwards changes the meaning entirely — watch the arrows and polarity markings.

Reference

A few common ANSI vs IEC differences

The same component is drawn differently under the two standards; watch for this when reading mixed sources.

ComponentANSI (US)IEC (international)
ResistorZigzag lineRectangular box
InductorContinuous semicircle coilsRectangle or coil
DiodeTriangle + barSame as ANSI

ANSI/IEEE Y32.2 and IEC 60617.

FAQ

Common questions, answered in 3 minutes

How do you tell NPN and PNP symbols apart?

Look at the emitter arrow direction: NPN points outward (Not Pointing iN), PNP points inward (Pointing iN Proudly). This also corresponds to the current direction.

Why is a resistor drawn as a rectangle in some places and a zigzag in others?

The zigzag is the US ANSI style and the rectangle is the international IEC style; they mean the same thing. European sources mostly use the rectangle.

How do you read the polarity of a polarized capacitor?

The straight-line side (solid plate) is the positive terminal and the curved side is the negative; reverse-connecting an electrolytic capacitor can make it bulge or even burst.

Are all ground symbols the same?

The common three decreasing horizontal lines mean "signal/earth reference"; chassis ground and analog/digital ground have their own variants, which complex systems distinguish.

Are these symbols an official national standard?

This table is drawn following common ANSI/IEC conventions to help you read schematics from various sources; for formal drafting, follow the standard and EDA library adopted by your project.

Data Provenance

Standards and sources referenced by this tool

Item Value / Formula Source
US symbols ANSI/IEEE Y32.2 IEEE
International symbols IEC 60617 IEC

Symbols are illustrative; for formal drafting, refer to your project standard / EDA library as authoritative.

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