# does a pushed button with I and O on it mean it is on or off

I am trying to charge a childs electric car. It says to make sure it is in the off position while charging. However, it is a button that goes in or out. How do I know whether pushing the button in turns it off or turns it on?

• Spring based buttons close the circuit when they are pushed in, and open the circuit when push out. I'll let an engineer with experience shine light on the rationale for this design and perhaps alternate designs we may see today in manufacturing. pinterest.ca/pin/467600373804353414 Oct 20, 2018 at 22:49
• Meaning, when it’s pushed in - it’s on, when pushed out - it’s off Oct 20, 2018 at 22:51
• If its designed properly a light will come on showing that its turned on (or some red bit on the button will show). Users don't read ISO standards. Oct 22, 2018 at 20:29

• 1 = On
• 0 = Off

These symbols come from binary.

Spring based buttons close the circuit when they are pushed in (1), and open the circuit when push out (0). I'll let an engineer with experience shine light on the rationale for this design and perhaps alternate designs we may see today in manufacturing.

You can see a push button diagram here.

You’re describing a push button switch. When the switch is pushed in, the circuit is closed and the power is on. The line symbol means “power on” and the circle symbol means “power off”. The presence of both (I/O) on a push button means the switch toggles the power.

Power symbols are defined by ISO 7000 / IEC 60417 and IEEE 1621, and were recently added to Unicode.

(source: https://unicodepowersymbol.com)

Here’s a great video on the history of the power symbol, https://youtu.be/VKCFDBPvJ74. It turns out the symbols are intended to improve user experience by providing a universal alternative to the English words on and off.

Yes, in old toys and appliances, the standard patterns has always been that

Pushed In = On | Pushed Out = Off

So it must be that. Nevertheless, there always should be a good feedback mechanism so that users always feel in control and this question doesn't even arise at the first place