A quick Wikipedia search explains the history and evolution of the power button. In the infancy of technology, “on” and “off” were used to denote states of power on switches and consoles. As time went on and the understanding of computers grew to larger and larger audiences, “on” and “off” were replaced with 1s and 0s (in the very base understanding of coding, the binary language of 1s and 0s create instances of checks, as in “yes, no, yes, yes, yes, no” for the input “101110”) to denote on and off, respectively. Eventually as user interfaces improved, the two where combined to form one singular button, as seen in the header. And that’s the brief history of the power button.
Anyway, when we look at the power button as a sign, that history is what we are seeing: the 1 and the 0 smashed together to form a new symbol that signifies the state of power for whatever technological device it’s attached to. The power symbol is the signifier. The concept of “this button can change the power state of this device from on to off and vice versa” is the signified. The user understanding and cultural acceptance of this dynamic, as a whole, is the sign. The ideological frame is the user base (all modern peoples who use electronic devices, so probably not the Sentinelese tribe).
Denotatively, if we ignore the history of words in general and just focus on this symbol exclusively, the symbol tells us that the concepts of “on” and “off” live within the button that the symbol is printed on. Connotatively, we get all of the societal additions of meaning and what the power can do to a device. In the digital setting, we understand that the button could also imply “reset” or if the device is malfunctioning the button serves as a sort of “redo”.
Who cares? Well first of all, UI designers. But our understanding, on a global level as a people, of how electronic devices function is a testament to our technological achievements. With the printing press came literacy and with the computer comes programming not only for code monkeys, but also for larger and larger audiences that turn to computer programming to solve problems (this is happening now as coding is beginning to become implemented in schools as core curriculum). So the power button, already containing within its existence a brief history of the computer and the society that grows with it, will continue to evolve (as we see now with iPhones omitting the symbol altogether). This symbol, even if not long for this world, stands as a signifier saying “I am the button, among several, you are looking for to make this thing work” (And perhaps even “its all a series of ons and offs to make it work in the first place”).
