1. UNIVERSAL COLLEGE OF ENGG. AND TECH.

2. B IPOLAR J UNCTION T RANSISTORS EE314

3. The transistor was probably the most important invention of the 20th Century, and the story behind the invention is one of clashing egos and top secret research. First - BJTs Reference: Bell Labs Museum B. G. Streetman & S. Banerjee ‘Solid State Electronic Devices’, Prentice Hall 1999.

4. Point-Contact Transistor – first transistor ever made

6. First Bipolar Junction Transistors W. Shockley invented the p-n junction transistor The physically relevant region is moved to the bulk of the material

7. Understanding of BJT force – voltage/current water flow – current - amplification

8. Basic models of BJT Diode npn transistor pnp transistor

9. Basic models of BJT

10. BJTs – Basic Configurations Fluid Flow Analogy Difference between FET (field effect transistor) and BJT Technology of BJTs pnp BJT npn BJT

11. BJTs – Practical Aspects Heat sink

12. BJTs – Testing

14. R ECALL P - N JUNCTION P N W V appl > 0 - + N P W V appl < 0 - + Forward bias, + on P, - on N (Shrink W, V bi ) Allow holes to jump over barrier into N region as minority carriers Reverse bias, + on N, - on P (Expand W, V bi ) Remove holes and electrons away from depletion region I V I V

15. B IPOLAR J UNCTION T RANSISTORS : B ASICS + - + - IEIE IBIB ICIC I E = I B + I C ………(KCL) V EC = V EB + V BC ……… (KVL)

16. BJT CONFIGURATIONS ECE 663 GAIN CONFIG

17. B IPOLAR J UNCTION T RANSISTORS : B ASICS ECE 663 Bias ModeE-B JunctionC-B Junction SaturationForward ActiveForwardReverse InvertedReverseForward CutoffReverse

18. BJT F ABRICATION ECE 663

19. PNP TRANSISTOR AMPLIFIER ACTION ECE 663 IN (small) OUT (large) Clearly this works in common emitter configuration

20. C OMMON B ASE DC CURRENT GAIN - PNP Common Base – Active Bias mode: ECE 663 I C =  DC I E + I CB0 I Cp =  T I Ep =  T  I E I C =  T  I E + I Cn  DC =  T 

21. C OMMON E MITTER DC CURRENT GAIN - PNP Common Emitter – Active Bias mode: ECE 663 I E =  DC I B + I CE0  DC =  DC /(1-  DC ) IEIE IBIB ICIC I C =  DC I E + I CB0 =  DC (I C + I B ) + I CB0 I C =  DC I B + I CB0 1-  DC GAIN !!

22. C OMMON E MITTER DC CURRENT GAIN - PNP ECE 663 Thin base will make  T  1 Highly doped P region will make   1

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