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In the common emitter circuit as shown in Fig, the value of the current gain is 100. Find `I_(B),V_(CE),V_(BE),V_(BC)` when `I_(C)=1.5mA`. The transistor is in active, cutoff or saturation state. |
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Answer» Here, `beta=100,I_(C)=1.5xx10^(-3)A, V_(C C)=24V`, `R_(B) = 220 xx 10^(3) Omega, R_(C) = 4.7 xx 10^(3) Omega` `I_(B)=I_C/beta=(1.5xx10^(-3)A)/100=15xx10^(6)A` In a close circuit GDCEFG `V_(CE)=V_(C C)-I_CR_C` `=24-(1.5xx10^(-3))xx(4.7xx10^(3))=16.95V` In a close circuit GDABEFG `V_(BE)=V_(C C)-I_B R_B` `=24-(15xx10^(-6))xx(220xx10^(3))=20.7V` In a closed circuit ABCDA `V_(BC)=I_C R_C-I_B R_B` `=(1.5xx10^(-3))xx(4.7xx10^(3))-(15xx10^(-6))xx(220xx10^(3))` `=3.75V` Since `V_(BE)gtV_(CE)`, so both the junction of transistor are forward biased. Therefore, the transistor is in a saturation state. |
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