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PN Junction / DIODE

PN Junction / DIODE. Bollen. SEMICONDUCTOR Pure silicium P material boron doped N material stibium doped P material and N material PN junction PN junction layer 0V7 PN junction characteristic. DIODE characteristic DIODE DC and ac resistance DIODE load line DIODE flipped resistorline

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PN Junction / DIODE

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  1. PN Junction / DIODE Bollen

  2. SEMICONDUCTOR Pure silicium P material boron doped N material stibium doped P material and N material PN junction PN junction layer 0V7 PN junction characteristic DIODE characteristic DIODE DC and ac resistance DIODE load line DIODE flipped resistorline DIODE DC resistance DIODE ac resistance AGENDA Bollen

  3. Pure silicium • 4 electrons • Ideal is to have 8 • So share withyourneighbour • Co-valencebounding • Electricalneutral Semiconductor, pure silicium Bollen

  4. Pure silicium • 4 electrons • Ideal is to have 8 • So share withyourneighbour • Co-valencebounding • Electricalneutral Semiconductor, pure silicium Bollen

  5. P material = silicium (+4) boron (+3) doped Boron misses 1 positvie charge (positon) & 1 negative charge (electron) Co-valence bounding Electrical neutral P material misses one electron, or has a place for one electron, this is called a free hole Semiconductor, P material boron doped Bollen

  6. N material = silicium (+4) stibium (+5) doped Stibium has got extra 1 positive charge (positon) & 1 negative charge (electron) Co-valence bounding Electrical neutral N material has got one extra electron out of the bounding, this is called a free electron Semiconductor, N material stibium doped Bollen

  7. P material = Free holes N material = Free electrons P material and N material Bollen

  8. PN junction Anode = P=material Kathode = N material KNAP = handsome K = Negative A = Positive Bollen

  9. Depletion layer can be made Wider by external reverse voltage Smaller by External froward voltage Depletion layer; Uth = 0V7 PN junction, depletion layer 0V7 Bollen

  10. Forward Depletion layer is gone Ud > 0V7 Current can flow Reverse Depletion layer is wider Ud < 0V0 Current can NOT flow PN junction, characteristic Bollen

  11. a Diode Is a one way street for current Diode, characteristic Bollen

  12. Assumption Treshold Voltage for silicium Ud = 0V7 for germanium Ud = 0V2 Diode, characteristic Bollen

  13. Diode, characteristic Where id = diode current Vd= diode voltage KT/q = 26 mV Iss = leakage current (1uA) Bollen

  14. Diode, DC and ac resistance Bollen

  15. Diode, Load line How to calculate the exact value of vd and id; Graphical; use load line, indicates the load of the diode Bollen

  16. Diode, Load line For shure id = ir = i For shure vs = vd + vr Bollen

  17. For shure For shure id = ir = i vs = vd + vr Diode, Load line Bollen

  18. Flip the resistor line and push the two curves horizontally to fit; vs = vd + vr Diode, Flipped resistor line Bollen

  19. Diode, Load line The flipped resistor line is called LOAD-LINE Bollen

  20. For DC resistance use the load line method For large voltages normally Vd= 0V7 is used Diode, DC resistance Bollen

  21. Diode, ac resistance Differentiating gives Rd = Δvd/Δid = 26 mV / Id Where kT/q = 26 mV Bollen

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