Can someone clarify the overall purpose and implications of biasing a BJT Class A amplifier? I just can't get my head wrapped around the entire purpose. As far as I know, biasing the circuit will place it in a certain operating region, but I don't know the limits/implications of doing this. Example from book: "Consider the operation of the emitter follower circuit for sine-wave input. Neglecting V_CEsat we see that if the bias current I is properly selected, the output voltage can swing from -V_CC to +V_CC with the quiescent value being zero." What constitues a "properly selected" bias current I and why does this gave way to the output being able to swing between -V_CC and +V_CC?