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?
- 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.
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.