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ECE 440 Homework XIII Spring 2006 Due: Wednesday, April 05, 2006 1. Sketch the energy band diagram for an n-p-n transistor in equilibrium (all terminals grounded) and also under normal active bias (emitter junction forward biased, collector junction reverse biased). With the emitter terminal grounded, determine the signs (positive or negative) of the collector voltage V CE and base voltage V BE , relative to the emitter, that correspond to normal bias. 2. A symmetrical p + -n-p + Si bipolar transistor has the following properties: Emitter/Collector Base A = 10 -4 cm 2 N a = 10 18 /cm 3 N d = 10 16 /cm 3 W b =1 μm τ n = 0.1 μs τ p = 10 μs μ p = 100 cm 2 /V-s μ n = 1060 cm 2 /V-s μ n = 350 cm 2 /V-s μ p = 380 cm 2 /V-s (a) Determine if the straight-line approximation can be applied to evaluate the excess carriers in the base region. (b) With V EB = 0.5 V and V CB = - 3 V, calculate the base current I B , assuming perfect emitter injection efficiency.
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This note was uploaded on 12/01/2011 for the course ECE 340 taught by Professor Leburton during the Spring '11 term at University of Illinois, Urbana Champaign.
- Spring '11