1. For an npn BJT, what are the cutoff mode, forward active mode, and saturation mode of operation? Please describe using your own words.
2. Assume a silicon npn bipolar transistor at T = 300 K has the following minority carrier parameters: DE = 8 cm2/s, DB = 20 cm2/s, DC = 12 cm2/s, τE0 = 10-8 s, τB0 = 10-7 s, and τC0 = 10-6 s. αT = δ = 0.9967, xB = xE = 1 μm, NB = 5 × 1016 cm-3, and NE = 5 × 1018 cm-3. Determine the common-emitter current gain β. Please provide the process of derivation.
