{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

N_BJT_sedra_N10

# N_BJT_sedra_N10 - Bipolar Junction Transistors(BJTs(10 1...

This preview shows pages 1–5. Sign up to view the full content.

1 Bipolar Junction Transistors (BJTs) (10)

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
2 BIPOLAR JUNCTION TRANSISTORS (BJT’s) Question 5.1 : Consider an npn transistor with v BE = 0.7 volts at i C = 1 mA. Find v BE at i C = 0.1 ma and i C = 10 mA? Answer: 0.64 Volts and 0.76 Volts Question 5.2 : Transistor of a certain type are specified to have β values in the range 50 to 150. find the range of their α values? Ans. 0.980 and 0.993 Question 5.3 : Measurement of an npn BJT in a circuit shows the base current to be 14.46 μ A, the emitter current to be 1.460 mA, and the base-emitter voltage to be 0.7 V. For these conditions, calculate α, β and I S ? Ans. 0.99, 100, 10 -15 A Question 5.4: Calculate β for two transistors for which α = 0.99 and 0.98. For collector currents of 10 mA, find the base current of each transistor? Ans. 99, 49, 0.1 mA , 0.2 mA
3 BIPOLAR JUNCTION TRANSISTORS (BJT’s) § 5.2.1 Circuit Symbols and Conventions The physical structure used thus far to explain transistor operation is rather cumbersome to employ in drawing the schematic of a multi-transistor circuit. Fortunately, a very descriptive and convenient circuit symbol exists for the BJT. Figure 5.13(a) shows the symbol for the npn transistor; the pnp symbol is given in Fig. 5.13(b). In both symbols the emitter is distinguished by an arrowhead . Figure 5.13 Circuit symbols for BJTs.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
4 BIPOLAR JUNCTION TRANSISTORS (BJT’s) § 5.2.1 Circuit Symbols and Conventions This distinction is important because, as we have seen in the last section, practical BJTs are not symmetric devices. The polarity of the device ------- npn or pnp -------- is indicated by the direction of the arrowhead on the emitter. This arrowhead points in the direction of normal current flow in the emitter, which is also the forward direction of the base-emitter junction. Since we have adopted a drawing convention by which currents flow from top to bottom , we will always draw pnp transistors in the manner shown in Fig. 5.13 (i.e. , with their emitters on top).
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern