Semiconductors are materials between conductors and insulators in electrical conductivity. Impurities (doping) can modify semiconductor properties significantly. Two differently doped regions form semiconductor junctions. Silicon and germanium are most common semiconductors
Amplifier increases signal magnitude using electric power. Amplifier is a two-port circuit with power gain greater than one. Can be separate equipment or internal circuit within another device
First integrated circuit was created by Jack Kilby in 1958. Robert Noyce developed first true monolithic IC using planar process. MOSFET technology enabled high-density integration in 1960s. Moore's law predicted doubling of transistors every two years
System bus combines data, address, and control buses for computer components. Early computers used ad-hoc wiring with backplanes for PCBs. Integrated circuits reduced computer unit size and standardized buses. DEC implemented memory-mapped I/O in PDP-11 around 1969
Microcomputers became most common in late 20th century. Includes desktops, rackmounts, laptops, tablets, smartphones, and gaming consoles. Term "microcomputer" has fallen into disuse
High current drive capability up to 200mA. Temperature stability of 0.005%/°C. Timing from µSec to hours. Turn off time less than 2µSec