34.fixed bias without re
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This document discusses fixed biasing of a BJT transistor in common emitter configuration. It explains how to analyze the bias circuit by locating the base-emitter and collector-emitter loops. The BE loop equation is derived as IB = (VCC - VBE)/RB. The CE loop equation is derived as VCE = VCC - ICRC. Constructing and simulating the fixed bias circuit allows determining the transistor's IC, IB, VCE, VB, VC, and VBC voltages.
34.fixed bias without re
- 2. Objectives 2 At the end of the module the student would be able to explain Study Fixed Biasing
- 3. Fixed Base Bias Circuit 3 This is common emitter (CE) configuration 1st step: Locate capacitors and replace them with an open circuit 2nd step: Locate 2 main loops which; BE loop CE loop
- 4. Fixed Base Bias Circuit 4 1st step: Locate capacitors and replace them with an open circuit
- 5. Fixed Base Bias Circuit 5 2nd step: Locate 2 main loops. BE Loop CE Loop 1 1 2 2
- 6. Fixed Base Bias Circuit 6 1 IB BE Loop Analysis VCC – IBRB – VBE = 0 Therefore, IB = (VCC – VBE)/RB
- 7. Fixed Base Bias Circuit 7 CE Loop Analysis VCC – ICRC – VCE = 0 VCE = VCC – ICRC IC But IC = βIB 2 VCE = βDC((VCC - VBE)/RB)
- 8. Fixed Base Bias Circuit 8 DISADVANTAGE Unstable – because it is too dependent on β and produce width change of Q-point For improved bias stability , add emitter resistor to dc bias.
- 9. Fixed Base Bias Circuit 9 Let us construct this circuit and find the following parameters IC, IB, VCE, VB, VC, VBC.
- 10. Fixed Base Bias Experiment 10
- 11. Simulation and Results 11 Run DC analysis with default settings Observe the outputs on the voltmeters and ammeters
- 12. Access it Online 12 You can access this experiment from the link below http://www.docircuits.com/public-circuit/378/bjt-fixed-bias-without-re