$3.50
TRANSITOR BAJA POTENCIA NPN 45V/0.5W
LINK´s INTERESANTES:
http://www.brighthubengineering.com/diy-electronics-devices/123008-understanding-small-signal-npn-and-pnp-transistors/
http://www.talkingelectronics.com/projects/200TrCcts/200TrCcts.html