Power symbol

Power On (IEC 60417-5007) and Power Off (IEC 60417-5008) symbols are used to indicate positions of the rocker switch
Power Button marked with Standby symbol (IEC 60417-5009) turns the device on or off without fully disconnecting power supply

A power symbol is a symbol indicating that a control activates or deactivates a particular device. Universal power symbols are described in the International Electrotechnical Commission 60417 standard, Graphical symbols for use on equipment, appearing in the 1973 edition of the document (as IEC 417) and informally used earlier.[1]

The well known on/off power symbol was the result of the logical evolution in user interface design. Originally, most early power controls consisted of switches that were toggled between two states demarcated by the words On and Off. As technology became more ubiquitous, these English words were replaced by the universal numeral symbols 1 and 0 (typically without serifs) to bypass language barriers. This "1" and "0" standard is still used on toggle power switches.

To create the symbol for a single on/off button, the "1" and "0" symbols were super-imposed onto each other to create the universally recognized power symbol used today.


IEC 60417-5007[2] (U+23FD POWER ON SYMBOL), the power on symbol (line), 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" means "on").
IEC 60417-5008[3] (U+2B58 HEAVY CIRCLE), the power off symbol (circle) 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").
IEC 60417-5009[4] (U+23FB POWER SYMBOL), 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. Alternatively, under IEEE 1621, this symbol simply means "power".[5]
IEC 60417-5010[6] (U+23FC POWER ON-OFF SYMBOL), the power on-off symbol (line within a circle), is used on buttons that switch a device between on and fully off states.
A waning crescent moon (U+23FE POWER SLEEP SYMBOL), indicating sleep mode, is added by IEEE 1621 as a replacement for the standby symbol.

Standby symbol ambiguity

Because the exact meaning of the standby symbol on a given device may be unclear until the control is tried, it has been proposed that a separate sleep symbol, a waning moon, instead be used to indicate a low power state. Proponents include the California Energy Commission and the Institute of Electrical and Electronics Engineers. Under this proposal, the older standby symbol would be redefined as a generic "power" indication, in cases where the difference between it and the other power symbols would not present a safety concern. This alternative symbolism was published as IEEE standard 1621 on December 8, 2004.[1][7][8][9]


Because of widespread use of the power symbol, a campaign was launched to add the set of characters to Unicode.[10] In February 2015, the proposal was accepted by Unicode and the characters were included in Unicode 9.0,.[11] The characters are in the "Miscellaneous Technical" block, with code points 23FB-FE.[12]

Power symbol as exhibit item at MoMA

The standby symbol, frequently seen on personal computers, is a popular icon among nerds. It is often found emblazoned on fashion items including T-shirts and cuff-links.[13] It has also been used in corporate logos, such as for Gateway, Inc. (circa 2002), Staples, Inc. easytech, Exelon, Toggl and others,[1] and even as personal tattoos. In March 2010, the New York City health department announced they would be using it on condom wrappers.[14] The 2012 TV series Revolution, set in a dystopian future in which "the power went out", as the opening narration puts it, stylized the last letter 'o' of its title as the standby symbol. The power symbol was a part of exhibition at MoMA.[15]

See also


  1. 1 2 3 Lawrence Berkeley National Laboratory (December 2002). "The Power Control User Interface Standard (consultant report)" (PDF). California Energy Commission. Retrieved 2007-04-26.
  2. "IEC 60417 - 5007, "ON" (power)". IEC.
  3. "IEC 60417 - 5008, "OFF" (power)". IEC.
  4. "IEC 60417 - 5009, Stand-by". IEC.
  5. Nordman, Bruce (2005-05-02). "Power Control Made Easy". EE Product News. Archived from the original on February 16, 2009. Retrieved 2007-04-26.
  6. "IEC 60417 - 5010, "ON"/"OFF" (push-push)". IEC.
  7. Lawrence Berkeley National Laboratory (December 2002). "Draft Standard for User Interface Elements in Power Control of Electronic Devices Employed in Office/Consumer Environments (consultant report)" (PDF). California Energy Commission. Retrieved 2007-04-26.
  8. "Save Energy at Your PC; Energy Scientists Propose Color-Coding Standard for PC Sleep Mode". American Institute of Physics. 2005-06-01. Retrieved 2007-04-26.
  9. "Power Management Controls - User Interface Standard - IEEE 1621". IEEE. Retrieved 2007-04-26.
  10. "Unicode Proposal 14009 Power Symbol" (PDF). Unicode. Unicode Consortium. Retrieved Dec 23, 2015.
  11. West, Andrew (2016-01-10). "What's new in Unicode 9.0?".
  12. "Unicode Chart - Miscellaneous Technical - Range: 2300–23F" (PDF). 2016-06-22.
  13. See for example "Adafruit's iCufflinks pulsate with the power of your Mac love".
  14. Smith, Robert (2010-03-09). "Official Condom Design: New York's New Sex Symbol". National Public Radio. Retrieved 2011-02-09.
  15. "MoMA | Is This for Everyone? New Design Acquisitions at MoMA". www.moma.org. Retrieved 2016-07-04.
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