The figures on the page:

http://www.allaboutcircuits.com/vol_3/chpt_4/2.html

illustrating use of a transistor as a switch are labeled incorrectly. The labels are:

(a) mechanical switch, (b) PNP transistor switch, (c) NPN transistor switch.

They Should be

(a) mechanical switch, (b) NPN transistor switch , (c) PNP transistor switch

Also, the battery should be reversed in case of the PNP transistor switch illustration, to maintain correct perception of comparison.

 

If you are talking about this drawing...

(a) mechanical switch, (b) PNP transistor switch, (c) NPN transistor switch.

I have to agree entirely.

For figure C I would switch battery polarity, and match it to (b)

 

(a) mechanical switch, (b) NPN transistor switch, (c) PNP transistor switch.

I swapped NPN and PNP at (b) and (c) above as suggested. Since the PNP at (c) is drawn upside down the battery polarity is correct as is; the collector is (-) battery.

copy at ibiblio is updated.