http://www.allaboutcircuits.com/vol_3/chpt_4/6.html

"It is called the common-collector configuration because (ignoring the power supply battery) both the signal source and the load share the collector lead as a common connection point:"

I'm confused, why is this called the common-collector if the collector on the transistor only connects to the positive side of the battery?

 

"Common" in this context does not mean "ground." It means "shared" or "mutual."

 

The input is connected to the Base
The output is connected to the Emitter

Whats left over? the Collector - hence its a common collector.

This works for all three configurations.

Try it!

 

In this case, the collector can be connected to Vcc or to ground. In the case of a NPN transistor, it will be connected to Vcc. In the case of a PNP transistor, it will be connected to ground.

So, it is better to think that "common" means that it is not connected to the input or the output, although it does not always means that the "common" is connected directly to ground or Vcc.

 

The collector is common to both the input and output.

 

Well OK. If you imagine the load power supply battery shorted out, then the signal source and the load share the Collector as a common point. I was imaging the power supply battery being open.

Thanks for the help guys.