I have a simple question:
Every book, tutorial, etc, that I see, shows when using a NPN transistor as a switch, you either need to have the base connected to voltage, and then it is on, or to ground, and then it is off. What I can't figure out is, why do you need to connect it to ground? Why can't you just leave it in the air?
For instance, the following is a common diagram:
(a)-> | |------LOAD----GRND
Why can't we just leave out section (a) ?
If anyone could help me, I'd really appreciate it, because I am stumpded.