In Dave's answer, he refers to the transistor as being the current sink. Now my question is this:
Imagine, hypothetically speaking, I have a P-Channel mosfet IRF4905. And I drive a resistive load of -20 amps through the Mosfet. I am also driving the base of the transistor with a 10V signal. Would the current through the transistor be the 10V/1000R or would the current seen through the transistor be 20amps as well?