Hard-drives have a definitive “on” status (they spin up, the heads move, and they use more electricity than when they are “off”). The same goes for a computer (fans and lights activate), monitors (relays click, electron-guns fire/LEDs light), and so on. But what about SSDs?
A hard-drive requires the disk to be spinning and the head to have power in order to read or write, but an SSD is more like RAM when it comes to reading and writing; it requires no movement, just a direct electrical write. Further, unlike RAM which needs to be continually refreshed to retains its contents, SSDs retain it after one write like hard-drives (SSDs are the best of both RAM and HD).
Therefore, do SSDs have a definitive on and off state or are they just a lump of electronics that sits there doing nothing until an actual read or write operation, and only use electricity then?
(Power-management may complicate things a bit since most devices are “turned off” while they still retain a trickle charge. Therefore, most devices are either “on”, “off”, or in “standby”. This doesn’t change the question though, since I’m asking about normal “on” usage, not standby.)
Thanks for the responses (I’m familiar with how electronics work; I recall all too clearly some of my uni exams), but all the current answers miss the crucial point to the question: a device (eg HD, monitor, etc.) that is “on” uses significantly more power than when it is off (or even standby).
Does this apply to SSDs as well?
Note: I had the thought that SSDs (including regular flash drives and memory cards) do seem to be “always on” in that they are immediately accessible. That is, unlike a hard-drive or optical drive which can spin down or at least take a moment to access when they reduce power, files stored on a flash drive are always instantly accessible no matter how much time has passed without it being accessed. (I suppose that could lead to the question do SSDs turn off (eg to conserve power) instead, but that would be a separate question, if even required—which it is not).