Well, BJTs are not voltage controlled devices, they are current devices. FETs are voltage controlled.
Engineering texts disagree with you. See especially Horowitz and Hill's Art of Electronics.
Also, "The Art of Electronics" is a great book for everything electronics and will serve as a reference for many things you may need some info on.
Um... Art of Electronics specifically teaches that BJTs are voltage controlled. It's accompanying lab-manual goes into great deatil about this. And just so there's no question:
When AOE author Win Hill was questioned about current-controlled BJTs, he had this to say:
http://cr4.globalspec.com/comment/720033/Re-Voltage-vs-Currenthttp://cr4.globalspec.com/comment/720374/Re-Voltage-vs-CurrentAlso, when there was an attempt on Wikipedia to use Art of Electronics to "prove" that BJTs are current-controlled, Win Hill came in on the BJT talk-page and put a stop to it. As he says, AOE does start out with Ic=hfe*Ib, then goes on to teach the more general voltage-control theory.
Dr. Hill points out that many common BJT circuits are based upon on the volt-control model, and Ic=Ib*hfe doesn't explain these. The current-gain model is a simplification. It's also a loosely-controlled variable in manufacturing, so circuits based on current-gain will fail when different transistors having identical part numbers are used. (Also fails if temperature varies by only a couple of degrees!) Current gain is obviously a very convenient rule of thumb, but brief investigation of BJT physics will show that Vbe directly determines Ic. Then of course Ib can affect Vbe. So Ib only controls Ic through the actions of Vbe changes.
OP, see where the contradictions arise? Grade-school electronics texts tend to teach physics misconceptions, and Electrical Engineers fight an uphill battle to stomp them out in online forums. Unfortunately most EE texts are non-intuitive, math not verbal/visual, so the non-EE audience gets little benefit.
Why does Vc need to be 0.2V above Ve? I picture it as follows. Ideally, the Vc-Ve difference should go all the way down to zero. It's because the ~0.7V diode drop across Vbe should be exactly equal to the ~0.7v diode drop across Vcb for the same current. Notice that the two 0.7V voltages are connected in series opposite. So they should subtract to zero: Vce is zero even while Vbe is 0.7v. However, BJTs are designed to give very low base currents. To do this we highly dope the emitter diode junction, and lightly dope the collector junction. The two diodes are not the same, so the junction voltages don't perfectly subtract to Vce=0. If you wanted BJT operation below Vce=0.2, you'd want a very symmetrical transistor with two identical junctions. But this gives you fairly high base currents in normal operation.
Great books on such topics are:
D. Ashby, "Electrical Engineering 101: Everything You Should Have Learned in School...but Probably Didn't"
Horowitz/Hill Art of Electronics, read an online copy via
google books