Hi Scott:
The symbols for "on" (1) and "off" (0) originated
in the days of the CEE (Europe) standards.
In those days, radios and other appliances were
built with big rotary switches, that ALSO turned
on the power. On a radio, the switch had numbered
positions which represented the receiving bands.
So, the switch would be marked 0-1-2-3-... The
0 position was the "off" position, and the 1-2-3...
positions were the "on" positions. Same for
kitchen mixers, heaters, and similar appliances
that had variable speeds and heat set by a rotary
switch with "on" positions of 1-2-3... and "off"
position at "0".
So, the CEE standards specified the marking "0"
for "off" and "1" or greater for "on."
Over the years, and with the introduction of
single-function two-position power switches, the
history of "0" and "1" was lost, and the numbers
morphed to the symbols "O" (circle) and "|"
(vertical line).
For safety purposes, a true power off is when the
switch disconnects the power from all of the
equipment (except, of course, the switch itself).
So, the marking "O" is reserved for such a switch
position and function.
Then came push-push switches, and "soft" switches
that control power through low-voltage that is
continuously on. This gave rise to the concept
of "standby" in place of an "off" that truly
disconnected ALL power.
These alternatives to a two-position "on"-"off"
switch required different symbols, hence the
symbols 5009 for the "soft" power control "on"
and "standby", and 5010 for the push-push switch,
push "on" and push "off".
The "on"-"standby" switch does not disconnect
power, but merely changes to a low-power state
where power to most of the circuits is indeed off.
The IEC description of 5009 is:
"On any kind of equipment. To identify the
switch or switch position by means of which
part of the equipment is switched on in order
to bring it into the stand-by condition."
Best regards,
Rich
From: [email protected] [mailto:[email protected]] On Behalf Of Scott Xe
Sent: Tuesday, July 10, 2007 7:26 AM
To: [email protected]
Subject: Symbol on power button
I notice that “I” + “/” + “Standby symbol” is on the power button
(actually not fully power off & in standby state). It appears on lots of
Japanese made products. What is the meaning in terms of technical aspects?
According to IEC 5009, it should be a “Standby Symbol” only. Your
guidance is appreciated.
Regards,
Scott
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