EE 2212

PROBLEM SET 6

S. G. Burns

Due: Wednesday, 17 November

NOTE 1: Table 5.2 on Page 228 is a very important reference for Problems 1, 2, and 3.

NOTE 2: You will find the loop equation V_CE=V_CB + V_BE very important in working on Problems 1, 2, and 3

1. Text 5.36 for an npn and Text 5.40 for a pnp. Include sketches of the bias voltages that are applied to each BJT terminal. This is good practice in using double-subscript notation.

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 (“current”) saturation in a FET!!!

For an npn BJT

VBE (in volts)	VCE (in volts)	BE Junction Bias (Forward or Reverse)	CB Junction Bias (Forward or Reverse)	Region Of Operation
+0.7	+5
-5	+5
-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

VBE (in volts)	VCE (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	+5

4. Draw and label the small-signal model for Figure P13.11 on page 830. Using your small-signal model, and by inspection of the resultant circuit topology, estimate the voltage gain, a_v = v_O/v_I. Observe the use of two dc supplies (independent ideal voltage sources)!

5. Draw and label the small-signal model for Figure P13.7 on page 830. Using your small-signal model, derive an expression for the voltage gain, a_v = v_O/v_I in terms of the circuit elements and model elements. No numerical calculations! Observe that this is a pnp BJT which makes no difference when working with the small-signal model. Compare your results with Problem 4.

6.      Small-Signal Analysis From An Old Quiz

          Assume that for the BJT, VA is finite and for the MOSFET, l is non-zero.  Assume the capacitors are considered large at the frequency of   interest. 

(a)   Sketch and label the small-signal model for this circuit.

(b)   Derive the voltage gain, av = vout/vin. Note that g_m is DIFFERENT for a BJT and a MOSFET.

A bit of humor if you can take it! Appropriate for those of you wanting to develop APPs

Pot-Pourri From My Vast Files Of Stuff

For your career and internship “guidance”

As you can observe from my Google calendar, I go to lots of ZOOM meetings, many with minimal outcomes.

You will also have many meeting “opportunities” during your engineering career. The following is so true:

EXTRA SPECIAL DEFINITIONS

Extracted, but filtered, from the IEEE Antennas and Propagation Group Newsletter and Other Sources

Plane Wave	Simplest way of signaling goodbye
Ordinary wave	The everyday kind
Wavelength	The duration of the farewell signal
Frequency	How many times do you wave
Wave guide	A book describing how to
Propagation	A method of continuing the species
Atmospheric duct	One that prefers flying to swimming
10^-15Bismol	One femto-bismol
10^-12 Boo	One picaboo
1 (boo)^2	One boo boo
10^-18 boys	One attoboy
10^12Bull	One terabull
10^1 Cards	One decacards
10^-9 Goats	One nanogoat
10^9Los	One gigalos
10^-1 Mate	One decimate
10^-2 Mental	One centimental
10^6 Phones	One megaphone
10^-6 Phones	One microphone
1000 Hurts	One kilohurts

Some of these definitions will help you in EMAGS and the antenna and transmission-lines courses. I have more of this but enough for now to minimize your nausea. I don’t want you dumping your lunch on your keyboard.

The following is appropriate for a BJT-focused problem set.