Coursework #1 EEE109
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Coursework #1 EEE109
September 19, 2023
1 Question 1 (10 Marks)
Silicon is doped with 5 × 1016 arsenic atoms/cm −3. Consider the following questions:
(a) Is the material n- or p-type? (2 marks)
(b) Calculate the electron and hole concentration at T=300K (4 marks)
(c) Calculate the electron and hole concentration at T=350K (4 marks)
2 Question 2 (15 Marks)
Consider the Zener Diode circuit shown in Figure 1. Consider the following parameters: VI = 20V, VZ = 10V, Ri = 220Ω and PZ (max) = 440mW.
(a) If the load resistor is RL = 380Ω. Please calculate the load current IL , zener diode current IZ , and input current II (6 marks)
(b) Determine the value of RL that will establish PZ (max) (5 marks)
(c) Repeat part of (b) if Ri = 175Ω (4 marks)
3 Question 3 (10 Marks)
The input voltage source is a square wave, as shown in Figure 2.
(a) Plot the waveform of output voltage Uo in circuit shown in Figure 3. Assume the turn-on voltage of the diode is Uγ = 0.6V. Please mark the maximum and minimum values on your figure. (5 marks)
(b) Plot the waveform of output voltage Uo in circuit shown in Figure 4. Assume the turn-on voltage of the diode is Uγ = 0.6V. Please mark the maximum and minimum values on your figure. (5 marks)
4 Question 4 (15 Marks)
The two diodes circuit is shown in Figure 5. Calculate the output voltage vo and the diode current ID1 and ID2 for the following voltage conditions:
(a) v1 = 10V and v2 = 0V (5 marks)
(b) v1 = v2 = 10V (5 marks)
(c) v1 = v2 = 0V (5 marks)
5 Question 5 (15 Marks)
A full wave rectifier circuit with battery charging is shown in Figure 6. Assume VB = 9V,Vγ = 0.7V and vs = 15sin[2π (60)t](V).
(a) Determine the resistance of R such that the peak battery charging current is 1.2A (5 marks)
(b) Determine the average battery charging current (5 marks)
(c) Determine the fraction of time that each diode is conducting (5 marks)
6 Question 6 (15 Marks)
The threshold voltage of each transistor in Figure 7 is VTP = −0.4V. Please determine the region of operation of the transistor in:
(a) The transistor in (I) (5 marks)
(b) The transistor in (II) (5 marks)
(c) The transistor in (III) (5 marks)
7 Question 7 (10 Marks)
An npn transistor with β = 80 ic connected in a common-base configuration, as shown in Figure 8.
(a) The emitter is driven by a constant-current source with IE = 1.2mA. Determine the value of IB , IC , α and VC (5 marks)
(b) Repeat part (a) for IE = 0.8mA (5 marks)
8 Question 8(10 Marks)
Consider the circuit shown in Figure 9. Use the Thevenin Equivalent Circuit to solve the following questions.
(a) Please determine the value of RTH , VTH , IBQ , ICQ , and VECQ for β = 90 (5 marks)
(b) Determine the percent change in ICQ and VECQ if for β is changed to for β = 150 (5 marks)
2023-10-25