# NMOS Model - Faculty of Engineering, Ain Shams University

## Transcription

NMOS Model - Faculty of Engineering, Ain Shams University

Ain Shams University Faculty of Engineering ECE Dept. CHEP Electronic Circuits COMM 361 Spring 2015 Dr. Sameh A. Ibrahim Exercise 1 PN Junction Diode Solutions 1. For the circuit depicted in Fig. 1, plot IX and IR1 as a function of VX for two cases: VB = -1 V and VB = +1 V. Fig. 1 Page 1 of 8 2. Assuming a constant-voltage diode model, plot Vout as a function of Iin for the circuits shown in Fig. 2. Fig. 2 Page 2 of 8 3. Plot the input/output characteristic of the circuits illustrated in Fig. 3 assuming a constant-voltage model. Fig. 3 Page 3 of 8 4. Beginning with VD,on ≈ 800 mV for each diode, determine the change in Vout if Vin changes from +2.4 V to +2.5 V for the circuits shown in Fig. 4. Fig. 4 Page 4 of 8 5. While constructing a full-wave rectifier, a student mistakenly has swapped the terminals of D3 as depicted in Fig. 5. Explain what happens. Use the exponential model. Fig. 5 Page 5 of 8 6. In this problem, we estimate the ripple seen by the load in Fig. 6 so as to appreciate the regulation provided by the diodes. fin = 60 Hz, C1 = 100 µF, R1 = 1000 Ω, and the peak voltage produced by the transformer is equal to 5 V. For simplicity, neglect the load. a. Assuming R1 carries a relatively constant current and VD,on ≈ 800 mV, estimate the ripple amplitude across C1. b. Using small-signal model of the diodes, determine the ripple amplitude across the load. Fig. 6 Page 6 of 8 7. We wish to design a circuit that exhibits the input/output characteristic shown in Fig. 7. Using ideal diodes, 1-kΩ resistors, and other components, construct the circuit. Fig. 7 Page 7 of 8 8. (Simulation) The half-wave rectifier of Fig. 8 must deliver a current of 5 mA to R1 for a peak input level of 2 V. a. Using hand calculations, determine the required value of R1. b. Verify the result by simulations. Fig. 8 Assuming VD,on ≈ 800 mV R1 = (2-0.8)/5m = 240 Ω Page 8 of 8