I have a question regarding bipolar transistor and it's operation as a switch.
I know that, in order to make transistor work as a switch, we need to avoid active region, meaning, we need to make transistor to work only in saturation and cut-off region.
This basically, cannot be implemented perfectly, but we can make transition period from saturation to cut off region as fast as possible, but I am not quite sure how to make transistor to work in cut off region, meaning, I want to know how to turn the transistor off correctly.
Let's take NPN transistor as an example:
The transistor is off if it's base-emitter and base-collector PN junctions are reverse-biased, however, that means that we would need significant negative voltage on base in order to do so, but I am wondering, how would this affect the circuit and transistor?
Another approach I've heard of is that we only need to make base-collector reverse biased and then we need to add a resistor between base and emitter, how is this any better? Do I need a resistor with huge resistance or with low resistance or it actually doesn't matter, and why?
Any help appreciated!