BJT PNP Switch: Why Vee Must Reach Zero for On

[likephysics]

In a BJT PNP switch, why does the base voltage need to go to zero to turn it on.
If Vee is 5V, the base has to be 5-0.7v to make the BE fwd biased.

 

[uart]

"In a BJT PNP switch, why does the base voltage need to go to zero to turn it on." - It doesn't

"If Vee is 5V, the base has to be 5-0.7v to make the BE fwd biased" - Correct.

 

[likephysics]

"In a BJT PNP switch, why does the base voltage need to go to zero to turn it on." - It doesn't

"If Vee is 5V, the base has to be 5-0.7v to make the BE fwd biased" - Correct.

Great. I just simulated it, it works.
Did the same thing last week, damn thing didn't work. That's why I doubted my understanding.

The reason I started with PNP switch is bcoz I don't understand why the VCE sat of PNP pass transistor (in voltage regulator) is much less than NPN Vce sat.