PB NO
Normally open pushbutton
A pushbutton contact normally shown open before actuation.
Schematic
Symbols · PB NC
Normally closed pushbutton
A pushbutton contact normally shown closed before actuation.
Schematic · PB NC
What it represents
A normally closed pushbutton has a contact closed in its specified normal state. Actuation changes that contact state according to the selected operator and contact block. Momentary, maintained, latching and positive-opening characteristics must be identified from device documentation.
A stop circuit is a common use, but the generic representation does not establish emergency-stop suitability or the required control-system behaviour. Operator labels, device specifications and the complete circuit remain necessary.
How to read it
- Identify the contact block and its parent operator.
- Read mechanical and contact characteristics from the manufacturer information.
Information to show or reference
- Show terminal designations.
- State the mechanical operating mode.
- Reference the complete circuit purpose and device selection.
A distinction that matters
An ordinary NC pushbutton and an emergency-stop device are not interchangeable solely because both drawings show a closed contact.
Sources you can follow
These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.
Pushbutton contact and actuator variants
Public NC pushbutton and actuator variants.
About this graphic
This illustration was authored independently by Elora Grid to explain the concept. It is not reproduced from a customer drawing, an official standard graphic or a manufacturer CAD file. Its correspondence to an exact IEC or IEEE symbol identifier has not been certified.
SVG and DXF downloads contain this original artwork. DXF uses unscaled drawing units; a GA envelope supplies no product dimensions, clearances or fabrication information. Original artwork is available under CC BY 4.0. Third-party references retain their own terms.
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