The transistor is typically built on a silicon base. The silicon atoms have fourteen neutrons and fourteen protons and are arranged in a lattice structure. Depending on how you dope, or implant small amounts of impurities into the silicon, the lattice structure can change slightly. These changes create either a p-type or an n-type base material. A p-type material has fewer electrons, creating “holes” or positively charged carriers, enabling current flow. An n-type material has more electrons, creating negatively charged carriers, enabling current flow through electrons. These p-type and n-type materials control the flow of electricity depending on the voltages applied. Both materials can be used in numerous combinations.