ETE444 :: Lec15

                         Dr. Mashiur Rahman




Copyright: Semiconductor Physics And Devices 3rd ed. - J....
Forward-active mode
Injection and collection of electrons
iE1= due to the flow of electrons injected into the base = ic




                                                        ...
Four operation mode of bipolar transistor




        n
Cuttoff mode
                                        VCB> 0
                                        VBE < 0
B-E = reverse ...
Forward active mode
                      The B-E junction becomes forward biased, an
                      emitter curren...
Inverse active
                    The B-E forward biased and C-B



VCB < 0
VBE < 0




   Minority carrier distribution
Saturation mode
                Both B-E and B-C junctions are forward
                biased and the collector current no...
Application
• Voltage amplifier by Bipolar Transistors
• Switching
Voltage amplifier by Bipolar Transistors
  Input sinusoidal signal voltage              Sinusoidal voltage across the Rc r...
Switching




                                                     Raise time   Storage time
                             ...
Switching :: Important parameter
• Current gain
  – lower doping in the base region is used.
• Switching time
  – The tran...
Ete411 Lec15
Ete411 Lec15
Ete411 Lec15
Ete411 Lec15
Ete411 Lec15
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Ete411 Lec15

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Lecture on Introduction of Semiconductor at North South University as the undergraduate course (ETE411)
=======================
Dr. Mashiur Rahman
Assistant Professor
Dept. of Electrical Engineering and Computer Science
North South University, Dhaka, Bangladesh
http://mashiur.biggani.org

Published in: Technology, Business
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Ete411 Lec15

  1. 1. ETE444 :: Lec15 Dr. Mashiur Rahman Copyright: Semiconductor Physics And Devices 3rd ed. - J. Neamen
  2. 2. Forward-active mode
  3. 3. Injection and collection of electrons
  4. 4. iE1= due to the flow of electrons injected into the base = ic ic  iE ic  iB α = Common-Base current gain β = Common-Emitter gain
  5. 5. Four operation mode of bipolar transistor n
  6. 6. Cuttoff mode VCB> 0 VBE < 0 B-E = reverse biased  Mejority carrier electrons from the emitter will not injected into the bias Minority carrier distribution
  7. 7. Forward active mode The B-E junction becomes forward biased, an emitter current will be generated and the injection of electrons into the base results in a collector current VCB> 0 VBE > 0 Minority carrier distribution
  8. 8. Inverse active The B-E forward biased and C-B VCB < 0 VBE < 0 Minority carrier distribution
  9. 9. Saturation mode Both B-E and B-C junctions are forward biased and the collector current no longer controlled by the B-E voltage. VCB< 0 VBE > 0 Minority carrier distribution
  10. 10. Application • Voltage amplifier by Bipolar Transistors • Switching
  11. 11. Voltage amplifier by Bipolar Transistors Input sinusoidal signal voltage Sinusoidal voltage across the Rc resistor Sinusoidal collector currents Sinusoidal base currents
  12. 12. Switching Raise time Storage time Fall time Circuit used for transistor switching Delay time
  13. 13. Switching :: Important parameter • Current gain – lower doping in the base region is used. • Switching time – The transistor can be doped with gold to introduce midgap recombination centers and thus reduce the switching time.

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