# MORE ABOUT SILICON

There's another way we can dope the silicon, by adding something having less electrons than the silicon itself. The resulting material also conducts electricity, but in a rather strange way. The electrons are all stuck in place like golf balls half buried in mud, but here and there is a "hole" where an electron should be but isn't. An adjacent electron can jump into the hole, so that the hole effectively moves in the opposite direction.
This kind of semiconductor is called p-type, and it behaves as though the holes were positively-charged particles carrying current from positive to negative. In this case, the conventional way of drawing the arrows is actually right!
P-type semiconductor also comes in two grades, lightly-doped P and heavily-doped P+. Their resistances are the same as the corresponding N types, and if all you want is a resistor or a connection, it doesn't matter which type you use.
However, as we'll see on the next page, they have some interesting properties when used together.