There are two symbols "I" and "O" on most power switches

What do these two symbols mean?

 

hi r,
'I'= ON, '0' = OFF
E

 

Think of the "I" as being a jumper to the power and the "O" as being Open therefore without power.

 

There are two symbols "I" and "O" on most power switches

What do these two symbols mean?

They represent the binary values zero and one, which are traditionally associated with logical "LO", "False", or "OFF" and "HI", "True", or "ON", respectively. In this context, they mean "OFF" and "ON".

 

[Sarcasm]
They are in Latin
The Latin word for "on" is "in" = I
The Latin word for "off" is (conveniently) "off" = O
[/sarcasm]
No matter how many stories you may be told, the | is simply a line, and the O is simply a circle.
they represent "on" and "off". Many people remember which is which by other lessons they've learned in life but the phrase, "the standard is the standard" applies here - it is just a line, and a circle.
the standards are (yes, a standard for each line and circle)...
Power On (IEC 60417-5007)
Power Off (IEC 60417-5008)
There is also a statement from IEC to dispel any rumors that they are binary one and zero.

 

No matter how many stories you may be told, the | is simply a line, and the O is simply a circle.

Beat me to it.

ak

 

 

The all inclusive version.

 

View attachment 281371
The all inclusive version.

That is officially called a "standby" button in IEC or an alternative power symbol in IEEE.
IEC 60417-5009 stand-by symbol,
IEEE 1621 power symbol

 

M.O.O.N, Moon!

 

I=ON, O=OFF

 

Note that in post #7, images 3 and 4 are switches that must be mounted horizontally; that is, rotated 90 degrees from their orientation in the images. Pedantically (?), the I and O are symbols, not characters. As such, their orientation is part of their definition.

Just
- Like
- - The
- - - Schematic
- - - - Symbol
- - - - - For

GROUND.

ak

 

View attachment 281372

M.O.O.N, Moon!

https://en.wikipedia.org/wiki/Power_symbol#Standards

ak

 

https://en.wikipedia.org/wiki/Power_symbol#Standards

ak

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

 

I = On
O = Off
This is a confusing matter for me also. Whenever I see I and O it makes me confused. It should be easy for everyone.
I just see the colour Green= On and Red = Off. It's better than I and O.

 

View attachment 281372

M.O.O.N, Moon!

Meh, maybe it's a bit old-school, but usually I prefer the ON/OFF duo as opposed to the dual-purpose (single) button. No good reason, really, just "feels right"....

 

I just see the colour Green= On and Red = Off. It's better than I and O.

Industrially there are two schools of thought regarding green and red indications.

The first is:

Green = go (on)

Red = stop (off)

The other is:

Green = safe (off)

Red = danger (on)

It seems to break down by industry.

 

The other is:

Green = safe (off)

Red = danger (on)

It seems to break down by industry.

A classic inversion if work / life imbalance. Then the employee takes this experience home and their spouse thinks they are complete idiots because they don't know the green light means the power is on.

 

Another school of thought:

A red button when pushed turns on the red light.
A green button is pressed to turn on the green light.

Now choose if red light means power is ON or not.

 

The fad of using blue LEDs for power indicators solves the red/green indicator problem.