Hi, i want to calculate V2/V1 in this circuit
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i've made some calculations
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but some errors are present: right answer should be last equation....what's wrong? thanks
Question about circuit problem homework
Oct 10, 2011
1 Replies
The Ib flowing into the base causes current (1+beta)xIb to flow in the emitter which in turn develops a voltage Ib x (1 +beta) x (re + R). Therefore the input circuit sees a resistance of (1+beta)x(re+R), which divides the Thevenin input voltage, not what you have. It is better to use the Norton equivalent input for this circuit anyway: current source V/Rs shunted by Rs in parallel with RB and (1+beta)x(re
+R). Then Ib is derived by inspection from the current divider rule: Ib=3D V1/Rs x (1/((1+beta)x(re+R))/( 1/Rs +1/RB + 1/((1+beta)x(re+R))), from which you derive V2=3D-IbxbetaxRL...Join the Discussion
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