I'm trying to understand transistors so I bought a couple and have been doing some reading, I basicly got it but some quick experiments have me dumbfounded.. I have the most basic NPN transistor circuit setup http://amasci.com/amateur/transis2.html like thatone, only with a loudspeaker instead.. Now, why does it still work as expected if I simply flip/reverse the transistor so the collector connects to the '-'poles on the batteries? This is actually the behaviour I've expected since NPN is symetrical, But I've understood that there is in fact a difference between the collector and the emitter. Enlighten me!!