- Emk11303 Electronics I Individual Assignmnet Due Date 27 05 2022 Chapter 3 Special Purpose Diodes The Zener Diode 1 A 1 (84.84 KiB) Viewed 32 times
- Emk11303 Electronics I Individual Assignmnet Due Date 27 05 2022 Chapter 3 Special Purpose Diodes The Zener Diode 1 A 2 (59.57 KiB) Viewed 32 times
- Emk11303 Electronics I Individual Assignmnet Due Date 27 05 2022 Chapter 3 Special Purpose Diodes The Zener Diode 1 A 3 (60.54 KiB) Viewed 32 times
EMK11303-ELECTRONICS I INDIVIDUAL ASSIGNMNET DUE DATE: 27/05/2022 CHAPTER 3-SPECIAL PURPOSE DIODES The Zener Diode 1. A certain zener diode has a V: =7.5 V and Z= 502 at a certain current. Show the V equivalent circuit (2 Marks) 2. From the characteristic curve in Figure 1. what is the approximate minimum zener current (Iz) and the approximate zener voltage at hx? (2 Marks) () 0 -10-9-8-2 V2(V) 3 4 9 10 11 12 13 Iz (m) Figure 1 3. When the reverse current in a particular zener diode increases from 20 mA to 30 mA, the Zener voltage changes from 5.6 V to 5.65 V. What is the impedance of this device? (2 Marks) 4. A zener has an impedance 1522. What is its terminal voltage at 50 mA if Vz4.7 V at 12 25 mA? (3 Marks) 5. Find the minimum input voltage required for regulation to be established in Figure 2. Assume an ideal zener diode with Izk=1.5 mA and Vz= 14V. (2 Marks) ( R 5600 VAN Figure 2 6. A loaded zener regulator is shown in Figure 3.V=5.17, at 1= 49mA. L=1mA, Z-72, and L= 70 mA. Find the minimum and maximum permissible load currents, (8 Marks) 8 w 220 IN4733A VN SV Figure 3 7. Find the load regulation expressed as a percentage in Problem 6. (2 Marks) 8. The no-load output voltage of a certain zener regulator is 8.23 V, and the full-load output is 7.98 V. Calculate the load regulation expressed as a percentage. (2 Marks) 9. In a certain zener regulator, the output voltage changes 0.2 V when the input voltage goes from 5 V to 10 V. What is the input regulation expressed as a percentage? (2 Marks) 10. In what type of circuit are tunnel diodes commonly used? (1 Marks) 11. What purpose do the reflective surfaces in the laser diode serve? Why is one end only partially reflective? (2 Marks) 2
CHAPTER 4- BIPOLAR JUNCTION TRANSISTOR AMPLIFIER A. Current Relationships 1. Explain, with the help of an example, the meaning of the term 'biasing (2 Marks) 2. What are the bias voltages (condition) need to be applied to an npn bipolar transistor such that the transistor is biased in the forward-active, cut-off and saturation modes of operations? Explain? (6 Marks) 3. With the aid of a diagram, state the relationships between collector, emitter and base currents in a bipolar transistor biased in the forward-active mode. (4 Marks) B. BJT Common-Emitter Amplifiers (DC Analysis) 1. The transistor parameters for the circuit in Figure 4 are B = 80 and V=0.7V The circuit elements are V SV. V. = 2.8V and R, = 32512 V* V 11 VEN RB VAN 1 VEC Relic Figure 4 Given that V=2Vdetermine: (a) base current, la ) (2 Marks) ) (b) collector current, Ic (2 Marks) (2 Marks) (c) emitter current, le (d) collector resistor, RC ) (3 Marks) (3 2. For the circuit shown in Figure 5. the transistor parameters are B-50. V=0.7V and Va=0.2V +5V Re=4400 - V Ry=64002 Vw Figure 5 Given that V, 3.6V, determine: - (a) output voltage, V. (5 Marks) 5 (b) base current, 1 ) (2 Marks) (c) collector current, I (2 Marks) (2 Marks) (d) power dissipated in the transistor. Pr 3. The circuit elements in Figure 6 are Ve=12V.V. - 8V. R=0.4612 R1.2652 and R, -3042 Voc Re&o lic VA w VCE VE Figure 6 Let Boe = 75 and Vw = 0.7V oc= (1) Determine: (e) base current, 18 , (1) collector current. Ic , (g) emitter current, le ( (h) collector-emitter voltage, VCE (2 Marks) (2 (2 Marks) 2 (2 Marks) 2 ) (2 Marks) (11) Sketch the DC load line (9 Marks)
4. Assuming Bpc =100, design the circuit in Figure 7 such that Ic - 1.5 mA and Vc = + 4 V. (5 Marks) +10 V Rc Vc -10 V Figure 7 C. BIPOLAR JUNCTION TRANSISTOR AS SWITCH 1. Determine IC(sat) for the transistor in Figure 8. What is the value of Is necessary to produce saturation? What minimum value of Vin is necessary for saturation? Assume VCE(sat) = 0 V. (4 Marks) +5V Σ10 ΚΩ Vio Ry w ΤΟ ΜΩ Poc = 150 Figure 8 2. The transistor in Figure 9 has a Bpc of 50. Determine the value of RB required to ensure saturation when Vin is 5 V. What must Vin be to cut off the transistor? Explain? Assume VCE(sat) = 0 V. (4 Marks) +15V 1.2 ΚΩ RE w Vive Figure 9 6/6