Quick Question About Transistor Voltage Drop

[Jerry]

In the above image, I was given everything in the diagram except for the two voltage drops I drew in red. All answers are correct, so there's no need to work out anything there.

What I'm having difficulty with is, to work out the voltages for Vrb and Vrc, I had to look up the answers to find out that Ve and Vce had no voltage dropped across them.

However, in the following Voltage Divider Bias example, both Ve and Vce have voltage drops.

So in the first image, how am I supposed to know straight away that there is no voltage drop for these values?

At first, I thought that since there was no component between the leg of the emitter and ground (Ve), there would be no voltage drop - fair enough; but why is the a voltage drop on Vc in that case? There is no component between the collector and Rc.

What confuses me most though, is understanding why there is no voltage drop between the collector and emitter (Vce), yet in the voltage divider example there is.

Please help if you can. Also, if you can keep answers as simple as possible, it'll help prevent confusion. Cheers.

[Jerome Trent]

V_e does not refer to a voltage drop.  It refers to the voltage at the emitter with respect to ground.  Since the emitter is connected to ground then that voltage is 0 volts. 

V_ce is a voltage that you can calculate.  This refers to the voltage at the collector with respect to the emitter therefore we use ce, collector to emitter.  You already found the voltage drop across the collector resistor.  So whatever voltage did not drop across the collector resister must be across the transistor collector to emitter.  We simply take the 20 volts Vcc in the collector circuit and subtract the voltage across the collector resistor. 

Since the emitter is connected to ground then: 

Now let’s consider your second circuit.  You refer to Ve and Vce as voltage drops.  This is the correct way to refer to Vce but Ve, again refers to the voltage at the emitter with respect to ground.  You are right in that there is a voltage at Ve and this is because there is an emitter resistor which will have a voltage drop across it.

This should explain now that both circuits have a voltage drop across the emitter and collector which is Vce.