In book four Hermione tells Ron and Harry that muggle electricity goes haywire in and around Hogwarts and they won't work. So, why do I see fan fics where everyone is walking about on their phones? They wouldn't work! And then they go around showing each other You Tube videos. Yeah they wouldn't be able to do that either. So remember kids no electricity or muggle technology in Hogwarts unless you want it to go crazy.