Semiconductor materials; intrinsic, N-type, and P-type semiconductor; carriers; density of state and Fermi function; Distribution of carriers; conductivity and drift current; Diffusion current; Einstein relationship; PN junction; depletion region characteristics ; forward and reverse biasing; diode I-V characteristics; diode circuits and applications; bipolar junction transistor: theory , DC biasing, and symmetrical swing; field effect transistor: theory, DC biasing, and symmetrical swing.