JoSS: Joy of Sharing Science No: 3

Your calculator is just a
bunch of electrical
switches
Zanyar Oğurlu, Eda Toprak, Mehmet Ekin Doğan
Revolutionized the electronics industry when it was invented in 1947,
transistors play a huge role in most of the electronic devices today.
They are the building blocks of many integrated circuits and are crucial
for logical operations. For simplicity, we are not going to discuss every
type of transistor but the first invented model called bipolar junction
transistor (BJT); however, we must also take into account that they are
not the most commonly used type of transistor. That title goes to
metal–oxide–semiconductor field-effect transistor (MOSFET) which is
far easier to mass-manufacture.
As you can see in the picture a BJT transistor has three legs, labeled as
E (Emitter), B (Base), and C (Collector) which are classified into two: P,
the material with fewer electrons or more ‘holes’ and N, the material
with more electrons or less ‘holes’ (The term ‘hole’ is used to represent
a missing electron.) The material with more holes is more positive
compared to its counterpart. In the PNP type of transistor, the current’s
direction won’t be aligned with the movement of electrons but
movement of holes. These P and N materials are arranged in such
ways that make the transistor function as if it was an electrical switch.