Power on/off symbol

How to read it

The line inside a complete circle is IEC 60417-5010, “on/off” (push-push): one button that connects the device to the mains and disconnects it. The draft of IEEE 1621 in Lawrence Berkeley National Laboratory’s 2002 report keeps it for a power switch that always switches to hard-off, where the device uses no power from the mains or its battery. For a button that leaves the device drawing some power when off, the same draft uses the Power symbol. Unicode encodes it as U+23FC, the power on-off symbol.

Also searched as: on off symbol, toggle power.

Differences by standard

Lawrence Berkeley National Laboratory’s table of office equipment symbols gives the IEC 60417 definition as a push-push button where off is the stable position and on lasts only while the button is held down. It notes that the ISO/IEC 13251 version of the same symbol ends differently, with each position, on or off, stable.

Look-alikes

The Power symbol has the line breaking through a gap at the top of the circle. Here the circle is closed and the line sits inside it.