Revise: Fundamentals of Electronics
Semiconductors, the transistor, integrated circuits, and logic gates.
Semiconductors
Semiconductors have controllable conductivity, often via doping (n-type/p-type).
Silicon computer chips rely on precisely doped semiconductor regions.
Transistor
Ξ² = I_C/I_B; a small base current controls a much larger collector current.
Ξ²=100 and I_B=0.02 mA gives I_C = 2 mA.
Logic Gate
AND: all inputs HIGH β HIGH output. OR: at least one input HIGH β HIGH output.
An alarm triggered only when BOTH sensors detect something uses an AND gate.
Integrated Circuit
An IC packs many components onto one chip, enabling small, cheap, reliable electronics.
A smartphone processor holds billions of transistors on one chip.