ECE 2212

EE 2212

PROBLEM SET 8

S. G. Burns

Due: 29 March 2017

Note: EXTRA CREDIT OPPORTUNITY: Up to 30 Points added to your end-of-the-semester Quiz Point Total. How do you earn this? I want circuit diagrams and specifications for power amplifiers and related equipment that you may have for some of your “stuff” and is usable, that is, supports in-class discussions when we get to power amplifiers towards the end of the semester. Information such as circuit diagrams, specifications for your sound systems, guitar amps, car stereos, powered sub-woofers, associated power supplies, speaker systems, etc. I define power loosely in that information on your portable electronics such as iPODs,mp3 players, smart phones, tablets, etc. also is interesting to me and appropriate for class discussion. I would like to borrow the material to supplement our class discussions on power amplifier circuits. Do not just go to the WEB for information that doesn’t relate directly to stuff you have. Hard Deadline for receipt of materials is class on Monday, 10 April. Earlier is better! Be sure your name is in the submitted materials. They will be returned. I will award up to 30 points based upon relevance and class usability and you describing the item and technical information to the class. The meaner and badder the better.

NOTE: Table 5.2 on Page 228 is a very important reference for Problems 1 and 2

1. Text 5.36 for an npn and Text 5.40 for a pnp. Include skectches of the bias voltages for each BJT.

2. This problem is an expanded version of Text 5.36. Complete the following table. To support each of your table entries, draw and label a symbol of the npn transistor and illustrate the junction bias conditions by showing the two diodes with the appropriate bias conditions. Your Region of Operation will be either forward-active, reverse-active, cutoff, or saturation. Observe that the definition for saturation in a BJT is entirely different than the definition for saturation in a FET!!!

For an npn BJT

V_BE (in volts)	V_CE (in volts)	BE Junction Bias (Forward or Reverse)	CB Junction Bias (Forward or Reverse)	Region Of Operation
+0.7	+5
-5	+5
+0.7	+0.2
-0.7	+5

3. This problem is an expanded version of Text 5.40. Complete the following table. To support each of your table entries, draw and label a symbol of the pnp transistor and illustrate the junction bias conditions by showing the two diodes with the appropriate bias conditions. Your Region of Operation will be either forward-active, reverse-active, cutoff, or saturation. Observe that the definition for saturation in a BJT is entirely different than the definition for saturation in a FET!!!

For a pnp BJT

V_BE (in volts)	V_CE (in volts)	BE Junction Bias (Forward or Reverse)	CB Junction Bias (Forward or Reverse)	Region Of Operation
+0.7	-5
-0.7	-5
+0.7	+0.2
-0.7	-0.2

4. Refer to Text Figure P5.26 given below. Modify the default BJT SPICE model to generate a set of curves that are a reasonable match to the characteristics shown in Figure P5.26. Submit the BJT non-default model parameters and a copy of the characteristic curves that you obtained. Key parameters to change will be β and VAF. We will discuss VAF in Monday’s class.

4. Text 5.95. Parts (a), (b), (c), and (d). Not Part (e)! Observe that you will have to derive an equation for the base current by summing current at the collector node.

5. Draw and label the small-signal models for Figures P13.3 and P13.6 on Page 829. We will cover this in Monday’s class.

Alternate definition for bipolar