Understand the difference.

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

TON NO

IEEE / ANSI

ANSI/IEEE on-delay normally-open contact symbol

The on-delay NO contact form specifically describes a delayed-closing transition. Its timer reference supplies the initiating condition and interval, while the unoperated contact remains open; release or reset behaviour comes from the documented timing chart.

Drawing use

Schematic

Application

Control circuits

Reference family

IEEE / ANSI / Manufacturer

Form evidence

Autodesk IEEE-oriented Time Delay Relays 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

A timed output contact differs from the timer coil or trigger that initiates its timing.

Full referenceAdd to legend

TON NO

Symbols

On-delay normally-open contact

An on-delay NO contact changes from its unoperated open state only after the associated timing condition has persisted for the documented delay. The contact tag links it to the timer element.

Drawing use

Schematic

Application

Control circuits

Reference family

IEC / Manufacturer

A distinction that matters

A timed contact adds transition information to the basic normally-open state.

Full referenceAdd to legend

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