The Meaning and Design Behind "On" and "Off"

April 19, 2011

The Meaning and Design Behind "On" and "Off"

Design, power, symbol

Jason Lang, over at Unplggd, shared an interesting bit of information on the symbology of power switches. It's something we don't think about much, since just moving or compressing a switch toward the opposite direction usually whirs a device to life. But there have been times when I've been unsure if I actually turned a device on or not, and then I find myself staring at the circle and line and wondering which switch is which. Never again!

According to Lang, The International Electrotechnical Commission (IEC) is the group behind the standard that provides the following definitions:

Design, power, symbol IEC 5007, the power on (line) symbol, appearing on a button or one end of a toggle switch indicates that the control places the equipment into a fully powered state. It comes from the binary system (1 or | means on)

Design, power, symbol IEC 5008, the power off (circle) symbol on a button or toggle, indicates that using the control will disconnect power to the device. It comes from the binary system (0 means off)

Design, power, symbol

Design, power, symbol IEC 5010, the power on-off symbol (line within a circle), is used on buttons that switch a device between on and fully off states.

Design, power, symbol

Design, power, symbol IEC 5009, the standby symbol (line partially within a broken circle), indicates a sleep mode or low power state. The switch does not fully disconnect the device from its power supply. This may appear on a toggle switch opposite a power on symbol, alone on a pushbutton that places the device into a standby state, or alone on a button that switches between on and standby.

Design, power, symbol A crescent moon, indicating sleep, is added by IEEE 1621 as a replacement for the standby symbol.

Design, power, symbol

There you have it! Though I was aware that many devices remain on standby (TVs, stereos, computers) I did not know that the broken circle power button is actually a symbol for that meaning, something good to know if you're trying to conserve/reduce electricity use.

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Via @strebel - Joshua Strebel

Photos by (from top to bottom) yum9me, Graham Ashton, James Blackman and Saverio Vigni

Jessica Patterson

Jessica Patterson

Hi, I'm Jessica. I'm a Designer and Writer at Drawbackwards and write for the Design Blog at I enjoy vintage things, letterpress, publication design, and long walks around the Cesar Chavez Park pond. You can follow me on twitter at @jessdoodled for lots of fun randomness.

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Graphic Designer / London, UK

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