# On a semiconductor chip, what state (on/off or read/write) corresponds to conducting or insulating behavior?

My textbook has a brief explanation of how semiconductors are used in modern computer chips because they can be made to conduct (by applying enough voltage to excite electrons across the band gap) or to insulate (by dropping the voltage to a lower level or shutting it off entirely) and this conditional, binary state can be used as an 'on/off' logic gate.

In modern computer systems, which state is "on" and which is "off"? In other words, is it the case that when we increase the voltage to cause conductance in the semiconductor that we have a "1" value and that when we drop the voltage down, we have a "0" value, or is it the other way around?

Or is it more appropriate to say "read" vs "write"?

Does the on/off or read/write state vary from one manufacturer to another? Or from one type of memory to another? I.e. does DDR SDRAM use conducting as "on" and insulating as "off" while other forms do it the other way around?

P.S. If comp sci isn't the right SE, please could you advise a better SE for this question?

In general it is conventional to use high voltage for true/one and low voltage for false/zero. In fact, a notation with the signal name overscored ($$\overline{SIGNAL}$$) is used to indicate active-low (alternatively SIGNAL#).