Electronics II

Daffodil International University Department of Electrical and Electronic Engineering Faculty of Engineering Midterm Examination, Fall-2026 Course Code: 0714-221 Course Title: Electronics-II Section: : A,B,C,D,E,F,G Level-Term: L2-T2 Teacher's Initial: MH , RS , MMJ Full Marks: 25 Exam Date: October 31, 2026 Time: 1.5 Hours [Note: Answer all the questions. CO's represent one of the learning outcomes of the course. Figure on the right hand side indicate marks allocated for the question] Q1. Explain the working of the op-amp circuit in Figure 1 as a Pulse Width Modulator (PWM). Using this explanation, determine Vs, Vs', Vk and ω so that the given output waveform is obtained. (From Figure 1) CO-1 (C2) [5] [Figure 1: Op-amp circuit as PWM with input V2 = 10 sin ωt, reference Vk, power supplies Vs and -Vs', and corresponding square wave output waveform Vo(t)] Q2. Calculate Output voltage of this circuit.(From Figure-2) CO-2 C(2) [5] [Figure 2: Multi-stage op-amp circuit with inputs 1.5 V and 2.25 V and output Vo] Q3. Calculate Voltage gain for the circuit below. (From Figure-3) CO-2 C(2) [Figure 3: Dual op-amp circuit with input vi and load resistor RL across output vo] Q4. Draw the output voltage waveform , Vo(t). (From Figure-4) CO-2 C(2) [5] [Figure 4: (a) Op-amp differentiator circuit with 0.2 μF capacitor and 5 kΩ resistor; and input triangular waveform Vi(V) versus t(ms)] Q5. Design a closed-loop op-amp circuit to implement the equation CO-2 C(2) [5] 3 (d^2 Vo / dt^2) - 5 (dVo / dt) + 2Vo = 4Vi