Presentation is loading. Please wait.

Presentation is loading. Please wait.

Semiconductors Chapters 19 20 22. Tubes Semiconductors.

Similar presentations

Presentation on theme: "Semiconductors Chapters 19 20 22. Tubes Semiconductors."— Presentation transcript:

1 Semiconductors Chapters

2 Tubes

3 Semiconductors

4 Silicon Atom

5 Germanium Atom (Less abundant than Silicon!!)

6 Intrinsic Material Pure Substance No Impurities!

7 Silicon Low Temperature – Poor Conductor High Temperature – Good Conductor Negative Temperature Coefficient Temperature Increases – Resistance Decreases

8 Silicon Si Covalent Bond Share 2e -

9 Doped Material – N-Type (electrons – majority carrier) Si AsSi As e-

10 Doped Material – P-Type (holes – majority carrier) Si Ga HOLE

11 N - Material e-

12 P Material e

13 P – N Type Material N Type: Negative Charge (-) P Type: Positive Charge (+)

14 Advantages of Semiconductors Smaller Low Power Cheaper High Efficiency Great Reliability Runs Cooler More Rugged Long Life Hazardous Environment Economic Production Less Noisy Made Part of an I.C. (Integrated Circuit)

15 Disadvantages of Semiconductors Susceptible to Temperature Changes. Extra components for Stabilization. Easily Damaged Exceeding Power Limits Reversing Polarity Excess Heat when Soldering

16 The PN Junction

17 P-N Junction PN Depletion Region An area that has no majority carriers. { e

18 P-N Junction e- + PN Barrier Voltage Build up of charge for each side. Must be overcome to conduct. {

19 Diode Operation e Reversed Bias (No Current Flow) Bias Voltage There is a small Leakage Current that can flow!!!

20 e- Diode Operation e Forward Bias (Current Flows) + Once the barrier voltage is exceeded!!

21 Forward Biased Diode E F is the Forward Voltage on the Diode E F for Germanium is 0.3V E F for Silicon is 0.7V

22 e Example: What is the Forward Biased Current (I F )? Germanium Diode R = 10kΩ Es= 9V E F = 0.3V IF=IF= ERER R E S - E F R = 9V - 0.3V 10kΩ = 0.87mA=

23 Diode Operation – Forward Biased e- + -

24 Current

25 Manufacturers Specifications Maximum Forward Current Maximum Reverse Voltage

26 One Directions!!!

27 Diode Symbol PN Cathode Anode

28 Diode Current Flow CathodeAnode

29 Diode Identification CathodeAnode White or Silver Line on Anode

30 Diode Construction Grown Junction Alloyed Junction Diffused Junction (Most Common)

31 Diode Testing Low Resistance High Resistance

32 LED – Light Emitting Diodes




36 + Hole Low Energy e-e- Electron High Energy

37 LED – Light Emitting Diodes + e-e- Electron and Hole Combine Light

38 Zener Diode Made to operate at a voltage greater than normal breakdown voltage. Manufacture with a specific voltage in mind. Voltage is determined by the resistance.

39 Zener Diode Symbol

40 Temperature Coefficient Positive – Breakdown voltage increases with Temperature. Operate in the 4 – 5 volt range Negative – Breakdown voltage Decreases with Temperature. Operate at less than 4 volts.

41 Silicon Controlled Rectifier (SCR) Gate Cathode Anode

42 Silicon Controlled Rectifier (SCR) I I Turn on Gate Diode Works!!!!

43 Transistor

44 Bipolar or Junction Transistor. Three layer device. Amplification Switch

45 N-P-N Transistor Base Collector Emitter N N P

46 P-N-P Transistor Base Collector Emitter P P N

47 Transistor Use Type NPN PNP Material Germanium Silicon Major Use High or Low power Switching High Frequency

48 Transistor Packaging

49 Part Number

50 Transistor Operation

51 Base Collector Emitter



54 N-P-N Transistor ++++ e- B C E IBIB ICIC IEIE Diode Turns On!!!

55 + P-N-P Transistor + e- B C E IBIB ICIC IEIE Diode Turns On!!! e

56 Transistor Testing - Resistance Forward – Low Resistance Reverse – Low High Resistance B C E

57 Transistor Testing

Download ppt "Semiconductors Chapters 19 20 22. Tubes Semiconductors."

Similar presentations

Ads by Google