Midterm Exam 1 Solutions 08

Midterm Exam 1 Solutions 08

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Unformatted text preview: ransistor and BJT-B is PNP transistor. Find the ratio of their current gains. (If you give correct qualitative answer, i.e., which BJT has higher current gain and why, you will get half credit). [6 pts] E B C E B C Emitter: N-type, N d = 1018 cm −3 Emitter: P-type, N a = 1018 cm −3 Base: P-type, N a = 1017 cm −3 N P N P N Base: N-type, N d = 1017 cm −3 P Collector: P-type, N a = 1016 cm −3 Collector: N-type, N d = 1016 cm −3 BJT-A BJT-B . Here, we must again use the assumption that , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , We have to look up all of these mobility values. Doing so, we find 300 cm /V s , 750 cm /V s , 150 cm /V s , 350 cm /V s , 3.030 Page 4 , , , , c) Answer this question qualitatively. For the two BJTs in Part a), which BJT will have larger Early voltage? Why? [4 pts] Device B will have a larger Early voltage (i.e., it will suffer less from the Early effect than device A). This is because the base width in B is larger than it is in A. This means that any chan...
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This note was uploaded on 01/24/2014 for the course EE 105 taught by Professor King-liu during the Spring '07 term at University of California, Berkeley.

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