Side-by-side reference

Understand the difference.

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

First referenceCompare with

IEEE / ANSI

ANSI/IEEE changeover contact symbol

The Form C relay contact representation links a common connection to alternative contact paths. The reader must identify common, normally closed and normally open terminals, with transition timing specified separately where overlap matters.

Drawing use: Schematic
Application: Control circuits
Reference family: IEEE / ANSI / Manufacturer
Form evidence: Autodesk IEEE-oriented Relays and Contacts functional form. Autodesk explicitly publishes this block under IEEE Symbol Preview. The counterpart is the matching functional concept; no equivalence of every detailed standard graphic is asserted.

A distinction that matters

Form C identifies a changeover contact arrangement; it does not by itself establish make-before-break behaviour.

Full reference

Symbols

Changeover contact

A changeover contact connects a common terminal to one of two alternative contact paths according to its operating state. Form C and SPDT are terms commonly encountered for this arrangement. The actual terminal numbering and transfer behaviour come from the selected device.

Drawing use: Schematic
Application: Control circuits
Reference family: IEC / IEEE / ANSI

A distinction that matters

Two unrelated NO/NC contacts are not automatically one changeover contact. Confirm whether they share a common connection and operating mechanism.

Full reference

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