Solving Circuit Problem with PNP-Common BJT Transistor

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SUMMARY

The discussion centers on solving a circuit problem involving a PNP-common BJT transistor, specifically analyzing emitter and collector currents under the condition of Vin=0V with an alpha value of 0.98. The user presents equations derived from Kirchhoff's rules for both the emitter and collector circuits, highlighting confusion regarding the presence of a +0.1V term in the collector circuit equation. The user successfully calculates the emitter current (Ie) as 0.002A and seeks clarification on the collector current (Ic) and base current (Ib) calculations, ultimately requesting textbook recommendations for further study on transistor examples.

PREREQUISITES
  • Understanding of PNP-common BJT transistor operation
  • Familiarity with Kirchhoff's circuit laws
  • Knowledge of current relationships in transistors (Ie = Ic + Ib)
  • Basic electronics principles, including voltage drops across junctions
NEXT STEPS
  • Study the derivation of transistor current equations in detail
  • Learn about the impact of beta (β) and alpha (α) in BJT circuits
  • Explore textbooks such as "Microelectronic Circuits" by Sedra and Smith for practical examples
  • Investigate simulation tools like LTspice for circuit analysis of BJTs
USEFUL FOR

Electronics students, circuit designers, and engineers seeking to deepen their understanding of BJT transistor behavior and circuit analysis techniques.

migelo
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Hi all. I'm new in this forum. and i thought to say welcome with a problem what makes me crazy. It is a pnp-common bjt transistor. made of silicon. the emittor current, the collector current and the base current are asked in the condition of Vin=0V. (alfa=0,98) However when the teacher wrote the kirchhoffs rule for the emittor circuit and the collector circuit, he wrote:

for the emittor circuit:
Vee-Veb-(1-alfa)Ie*50-49*Ie=0
he took 0,6 for the Veb cause it is silicon. it is ok. and from here Iee comes out 0,002A.

but for the collector circuit:
Vcc-Vcb-1,98Ic+0,1=0
how 0,1 can be here? there is Ib*Rb. right? we had found 0,002A for the Ie. and when put it in the Ie=Ic+Ib equation, and use the Ic=alfa*Ie, we found 0,00004A for the Ib. and if we multiply it with Rc; 50ohm, we found 0,002A. so where is the +0,1?

we asked the confusing to the teacher, however he didn't give us a saturating reply. so i thooght to ask it to you. i will be waiting for your answers.

and also, i generally need a textbook which has got plenty of example problems. (especially about transistors) could you give me some suggestions?
 
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http://img41.imageshack.us/img41/9358/circuitw.jpg
sorry, i forgot the circuit picture. here it is.
 
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