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Unformatted text preview: Lecture 30 Friday April 18 EE 332 Semiconductor Devices Problem Assignment Monday Æ Problems 9.2 and find the depletion widths at collector and emitter junctions for the transistor in problem 9.4 Problem 9.1 Are the Junctions Biased On or Off? Modes of operation 1. Normal (Active) V CB off & V BE on 2. Cutoff V CB off & V BE off 3. Saturation V CB on & V BE on 4. Inverted V CB on & V BE off Transistor (Normal Operation) Emitter p-n junction is forward biased and injects carriers into the base region. The width of the base region is less than the diffusion length, L. These carriers reach the collector depletion region and are sweep across the reverse biased junction. n-p-n Structure & p-n-p Biased Junctions Energy Band Diagrams The equilibrium energy band diagram for a BJT with uniform doping in each region. The energy band diagram for operation in the active mode. Normal Bias I-V Curves The common base configuration. The common emitter configuration. Note the different uses of the word Saturation.of the word Saturation....
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- Spring '08
- Bipolar junction transistor, P-n junction, energy band diagram, npn pnp npn pnp