1. BJT DC Circuits I

2. In this Lecture, we will:  Discuss further the dc analysis and design techniques of bipolar transistor circuits.  Examine some basic applications of bipolar transistor circuits.

3. DC Equivalent Circuit for npn Common Emitter

4. Load Line

5. Another Load Line Example (Example 5.10)

7. Problem-Solving Technique: Bipolar DC Analysis 1.Assume that the transistor is biased in forward active mode a.V BE = V BE (on), I B > 0, & I C = I B 2.Analyze ‘linear’ circuit. 3.Evaluate the resulting state of transistor. a.If V CE > V CE (sat), assumption is correct b.If I B < 0, transistor likely in cutoff c.If V CE < 0, transistor likely in saturation 4.If initial assumption is incorrect, make new assumption and return to Step 2.

8. Voltage Transfer Characteristic for npn Circuit

9. Voltage Transfer Characteristic for pnp Circuit

10. NPN Switch Driving a Load

11. BJT Switches Driving Loads

12. Digital Logic InverterNOR gate

13. Bipolar Inverter as Amplifier

14. Effect of Improper Biasing on Amplified Signal Waveform

15. Current Relationships in the Active Mode i E = (1+  )i B

16. Common-Base Configuration

17. Current-Voltage Characteristics of a Common-Base Circuit

18. Example Problem I

19. V + = 3.3V V - = -3.3V = 2.27V

20. Example Problem I

21. Example Problem II

25. Example Problem III