My professor presented the NOT gate in the Transistor-Transistor logic as the following:
Where V is always 5Volts. The two symbols are MOSFETs N-type transistors. The first transistor (which is always conducting) is called the Load transistor, and the second is the one who really does the logic operations. (By first I mean the top one, and second the bottom one).
What I'm unable to understand is why does this Load transistor exists. Can't we just plug the Drain of the other transistor directly in V? Why do we have to add a transistor between them?
Thanks in advance.