Understand the difference.

Compare the meaning, drawing context and source references of two entries. A similar graphic or shared abbreviation does not establish equivalence.

Coil

Symbols

Relay coil

A relay coil represents an operating element that changes the state of associated contacts when the device operates. Coil and contact representations are often drawn in different locations to make the circuit easier to read. Their shared identifier and cross-references establish the relationship.

Drawing use

Schematic

Application

Control circuits

Reference family

IEC / IEEE / ANSI

A distinction that matters

A relay coil is not a contactor power pole. Similar operating-element marks can represent equipment with different switching duties.

Full referenceAdd to legend

NO

Symbols

Normally open contact

A normally open contact is open in the normal state defined for the device. Operating its relay, pushbutton or other parent device may close the contact. The meaning of normal must be established from the drawing convention and equipment documentation; it is not necessarily the current live condition of the installation.

Drawing use

Schematic

Application

Control circuits

Reference family

IEC / IEEE / ANSI

A distinction that matters

Normally open describes the stated normal condition. A position indication or operating snapshot may use a different state convention.

Full referenceAdd to legend

Original educational previews. Follow the source references on each full entry for the appropriate standard or selected product.