Altium Designer Documentation

IEEE Symbols

Modified on Apr 11, 2017

Parent page: Schematic Objects

A placed IEEE Symbol (Sigma).


IEEE symbols are non-electrical drawing primitives. They are used for representing logic functions or devices. These symbols enable users to understand the logic characteristics of these functions or devices without requiring specific knowledge of their internal characteristics.


IEEE Symbol objects are available for placement in the Schematic Library Editor only. A total of 34 symbols are available, the associated placement commands for which are located:

  • On the Place » IEEE Symbols main menu.
  • On the IEEE Symbols drop-down () of the Utilities toolbar.
  • On the Place » IEEE Symbols right-click workspace context menu.

The range of IEEE Symbols available.


After launching a command, the cursor will change to a cross-hair and you will enter IEEE symbol placement mode. The chosen IEEE symbol will appear "floating" on the cursor.

  1. Position the object and click or press Enter to effect placement.
  2. Continue placing further symbols, or right-click or press Esc to exit placement mode.

Additional actions that can be performed during placement are:

  • Press the Tab key to access an associated properties dialog, from where properties for the symbol can be changed on-the-fly.
  • Press the Alt key to constrain the direction of movement to the horizontal or vertical axis, depending on the initial direction of movement.
  • Press the Spacebar to rotate the symbol anti-clockwise or Shift+Spacebar for clockwise rotation. Rotation is in steps of 90°.
  • Press the X or Y keys to mirror the symbol along the X-axis or Y-axis respectively.
  • Press the + or - keys (on the numeric keypad) to enlarge or shrink the symbol.

While attributes can be modified during placement (Tab to bring up associated properties dialog), bear in mind that these will become the default settings for further placement unless the Permanent option on the Schematic – Default Primitives page of the Preferences dialog is enabled. When this option is enabled, changes made will affect only the object being placed and subsequent objects placed during the same placement session.

Graphical Editing

This method of editing allows you to select a placed IEEE symbol object directly in the workspace and change its location or orientation, graphically. IEEE symbols are fixed with respect to their shape and can be resized only through use of the relevant keyboard shortcuts. As such, editing handles are not available when the IEEE symbol object is selected:

A selected IEEE Symbol (Sigma).

  • Click anywhere inside the dashed box and drag to reposition the symbol as required. While dragging, the symbol can be rotated (Spacebar/Shift+Spacebar), mirrored (X or Y keys to mirror along the X-axis or Y-axis respectively), or resized (+/- keys on numeric keypad).

If attempting to graphically modify an object that has its Locked property enabled, a dialog will appear asking for confirmation to proceed with the edit. If the Protect Locked Objects option is enabled on the Schematic – Graphical Editing page of the Preferences dialog, and the Locked option for that design object is enabled as well, then that object cannot be selected or graphically edited. Double click on the locked object directly and disable the Locked property or disable the Protect Locked Objects option, to graphically edit the object.

Non-Graphical Editing

The following methods of non-graphical editing are available:

Via an Associated Properties Dialog

Dialog page: IEEE Symbol

This method of editing uses the IEEE Symbol dialog to modify the properties of an IEEE symbol object.

The IEEE Symbol dialog.

The IEEE Symbol dialog can be accessed prior to entering placement mode, from the Schematic – Default Primitives page of the Preferences dialog. This allows the default properties for the IEEE Symbol object to be changed, which will be applied when placing subsequent IEEE Symbols.

During placement, the dialog can be accessed by pressing the Tab key.

After placement, the dialog can be accessed in one of the following ways:

  • Double-clicking on a placed IEEE symbol object.
  • Placing the cursor over a IEEE symbol object, right-clicking and choosing Properties from the context menu.
  • Using the Edit » Change command and clicking once over a placed IEEE Symbol object.

Not only can the dialog be used to change properties for the current IEEE symbol, it can also be used to change the symbol for a completely different one, simply by choosing the required new symbol type from the Symbol drop-down field.

Via the SCHLIB Inspector Panel

Panel pages: SCHLIB Inspector, SCHLIB Filter

The SCHLIB Inspector panel enables the designer to interrogate and edit the properties of one or more design objects in the active document. Used in conjunction with appropriate filtering - by using the SCHLIB Filter panel, or the Find Similar Objects dialog - the panel can be used to make changes to multiple objects of the same kind, from one convenient location.

Via the SCHLIB List Panel

Panel pages: SCHLIB List, SCHLIB Filter

The SCHLIB List panel allows the designer to display design objects from one or more documents in tabular format, enabling quick inspection and modification of object attributes. Used in conjunction with appropriate filtering - by using the SCHLIB Filter panel, or the Find Similar Objects dialog - it enables the display of just those objects falling under the scope of the active filter – allowing the designer to target and edit multiple design objects with greater accuracy and efficiency.


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