Logic Gates: NOT gate question

For example, if I were to place a single input, two NOT gates and an output in series, how is electricity generated in the middle of the two NOT gates? Or, more generally, if an input is off, where does the NOT gate get the electricity to generate it? Just a curiosity I've never worked out myself.

Thanks in advance.

For gates to work.. it needs supply apart from input... thats why.....

The digital components like AND, OR, NAND, NOR, NOT gates are IC (integrated circuits) they have an Vcc (+5v) and a ground, depending if the state is 0 or 1 they use a voltage level (0 or off = 0 - 0.8v ; 1 or on 2 - 5v) you can also check this link.

http://www.kpsec.freeuk.com/components/74series.htm