Presentation is loading. Please wait.

Presentation is loading. Please wait.

Semiconductor Devices II  Transistors have revolutionized Electronics and our way of life. Before transistors, computers were bulky, expensive, slow and.

Similar presentations


Presentation on theme: "Semiconductor Devices II  Transistors have revolutionized Electronics and our way of life. Before transistors, computers were bulky, expensive, slow and."— Presentation transcript:

1 Semiconductor Devices II  Transistors have revolutionized Electronics and our way of life. Before transistors, computers were bulky, expensive, slow and highly un-reliable. ELECTRONICS TECHNOLOGY

2 Semiconductor Devices II  Transistors have revolutionized Electronics and our way of life. Before transistors, computers were bulky, expensive, slow and highly un-reliable.

3 ELECTRONICS TECHNOLOGY Semiconductor Devices II  Transistors are a semiconductor device similar to diodes

4 Semiconductor Devices II  Transistors Transistors  Transistor Biasing Transistor Biasing ELECTRONICS TECHNOLOGY

5 Objective In this section we will learn: 1. configuration of the transistor, 2. Its usefulness 3. Its operating characteristics ELECTRONICS TECHNOLOGY Transistors Home

6 ELECTRONICS TECHNOLOGY Transistors Configuration  Transistors have two junctions instead of one as the case with a junction diode. Home PNPNPP Diode Transistor

7 ELECTRONICS TECHNOLOGY Transistors Configuration  Transistors Symbol is illustrated below. The identifier is Q Home NP N

8 ELECTRONICS TECHNOLOGY Transistors Configuration  Transistors Symbol is illustrated below. The identifier is Q. ( Negative-Positive-Negative and Positive-Negative- Positive) Home Collector Base Emitter Collector Base Emitter NPNPNP

9 ELECTRONICS TECHNOLOGY Transistors Configuration  NPN Transistors have the arrow pointing outward from the base. ( Note: N ever P oints i N) Home Collector Base Emitter NPN Collector Base Emitter PNP

10 ELECTRONICS TECHNOLOGY Transistors Configuration  PNP Transistors have the arrow toward the base. Home Collector Base Emitter NPN Collector Base Emitter PNP

11 ELECTRONICS TECHNOLOGY Transistors Configuration  The emitter is heavily doped and allows for electron flow in the semiconductor (notated by the arrow) Home Collector Base Emitter NPN

12 ELECTRONICS TECHNOLOGY Transistors Configuration  The base is thin and is lightly doped. This configuration allows for electron flow from Emitter to collector. Home NPN Collector Base Emitter

13 ELECTRONICS TECHNOLOGY Transistors Configuration  The collector is moderately doped and is the largest of the three. This allows for more heat loss. Home NPN Collector Base Emitter

14 ELECTRONICS TECHNOLOGY Transistors Identification  The identification standard is similar to the standard used on diodes. Home NPN 2N2222 Transistor Semiconductor Part Number

15 ELECTRONICS TECHNOLOGY Transistors Pin layout  The leads of a TO5 package are always configured as shown below… Home NPN E B C (bottom side)

16 ELECTRONICS TECHNOLOGY Transistors Pin layout  The leads of a TO-92 package are always configured as shown below… Home NPN C B E (bottom side)

17 ELECTRONICS TECHNOLOGY Transistors Pin layout  Power Transistors (type TO-3) are different. The collector is the case Home (bottom side) EB Collector (Side view)

18 ELECTRONICS TECHNOLOGY Transistors Biasing Objective  Understand the biasing of a transistor  Define Cutoff and Saturation  Define fixed, self and combinational biasing Home

19 ELECTRONICS TECHNOLOGY Transistor Biasing In order for a transistor to function as an amplifier, the BE junction must be forward biased. Home

20 ELECTRONICS TECHNOLOGY Transistor Biasing A minimum voltage V BE of.7 volts must be applied to forward bias the junction BE. Home V BE

21 ELECTRONICS TECHNOLOGY Transistor Biasing In order for a transistor to work properly as an amplifier, the Collector Base (CB) junction must be reversed biased. Home

22 ELECTRONICS TECHNOLOGY Transistor Biasing V BC must have a voltage level greater than V BE. Home V BC

23 ELECTRONICS TECHNOLOGY Transistor Biasing When V BC < V BE and reverse biased, current is forced to flow as illustrated. Home N P N

24 ELECTRONICS TECHNOLOGY Transistor Biasing Since the base material is very small compared to the collector, only a small amount of Current flows through I B. Home N P N

25 ELECTRONICS TECHNOLOGY Transistor Biasing With this information, I C =I B +I E. Home N P N

26 ELECTRONICS TECHNOLOGY Transistor Biasing Once the EB junction is forward biased and CB is reversed biased, Current will flow through the Transistor. Home

27 ELECTRONICS TECHNOLOGY Transistor Biasing Keep in mind the base is thin and lightly doped. Therefore little current flows through the base. Most of the current flows through the collector. Home

28 End of Presentation


Download ppt "Semiconductor Devices II  Transistors have revolutionized Electronics and our way of life. Before transistors, computers were bulky, expensive, slow and."

Similar presentations


Ads by Google