As long as there is a power switch on almost all electrical appliances, lamps and sockets, the two symbols “|” and “O” will inevitably appear
If we only look at the symbols to judge, what exactly do the “|” and “O” mean?
Can you tell which is the circuit connection and which is the circuit break?
Many people think that “O” means power on, and “|” means power off, because open means OPEN in English
Many switches use ON/OFF to represent opening and closing, the two symbols “|” and “O” In fact, it is the two letters “I/O” in English, which is the abbreviation of input/output
It means input and output, so of course “|” means power on, “O” means power off
The above points seem to be very reasonable, but they are all incorrect explanations. In fact, during World War II, in order to ensure the stable operation of electrical equipment, engineers needed to develop a set of general electrical equipment standards to unify the navy, air force and civil defense. , Electrical equipment in various fields such as logistics. The standard of switch and rotary switch, especially the logo of the switch, should ensure that only a few minutes of training are required, and soldiers and maintenance workers from different countries can recognize and use it correctly.
Some engineers thought of a simple solution, which is the international binary code. Since the “1” in the binary system represents “on” and “0” represents “off”, so there are “|” and “O” on the switch
Later, the International Electrical Engineering Committee (IEC) in the technical specifications compiled in 1973. It is formally proposed to use “|” and “O” as a mark of the power switch
The circle “O” represents the circuit is disconnected (that is, “turn off the light”)
The straight bar “|” represents the circuit is closed (that is, “turn on the light”)