Tut 2 - circuit analysis tutorials for chapter 1 PDF

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circuit analysis tutorials for chapter 1...

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Faculty of Engineering & IT P O BOX 3624 Ongwediva http://www.unam.na Department of Electrical Engineering

TECE3691 Electric Circuit Analysis I Tutorial 2 (15 February 2018) 1. Find the phase relationship between the following waveforms: 𝑣 = 2 cos(𝜔𝑡 − 30°) 𝑖 = 5 sin(𝜔𝑡 + 60°) 2. The current through a 20 inductive reactance is given. What is the sinusoidal expression for the voltage? Sketch the 𝑣 and 𝑖 sinusoidal waveforms on the same axis. a. 𝑖 = 5 sin 𝜔 𝑡 b. 𝑖 = 40 × 10−3 sin(𝜔𝑡 + 60°) 3. The voltage across a 1 F capacitor is given. What is the sinusoidal expression for the current? a. 𝑣 = 30 sin 200 𝑡 b. 𝑣 = 60 × 10−3 sin 377𝑡 4. For the following pairs of voltages and currents, indicate whether the element involved is a capacitor, an inductor, or a resistor, and find the value of C, L, or R if sufficient data are given: a. 𝑣 = 550 sin(377 𝑡 + 50°) 𝑖 = 11 sin(377 𝑡 − 40°) b. 𝑣 = 36 sin(754𝑡 − 80°) 𝑖 = 4 sin(754𝑡 − 170°) 5. The reactance of a coil equals the resistance of a 10 k resistor at a frequency of 5 kHz. Determine the inductance of the coil. 6. If the current through and voltage across an element are 𝑖 = 8 sin(𝜔𝑡 + 40) and 𝑣 = 48 sin(𝜔𝑡 + 40), respectively, compute the power by 𝐼2 𝑅, (𝑉𝑚 𝐼𝑚 /2) cos 𝜃), and 𝑉𝐼 𝑐𝑜𝑠 𝜃, and compare answers. 7. The power factor of a circuit is 0.5 lagging. The power delivered in watts is 500. If the input voltage is 𝑣 = 50 sin(𝜔𝑡 + 10°), find the sinusoidal expression for the input current.

8. For the network below, find the sinusoidal expression for source voltage (𝑣𝑠 ), 𝑖1 and 𝑖2 .

9. Express the following in phasor form: a) 20 sin(377𝑡 − 180°) b) 6 × 10−6 cos 𝜔𝑡 c) 3.6 × 10−6 cos(754𝑡 − 20°) 10. For the system below, find the sinusoidal expression for the unknown current 𝑖1 if: 𝑖𝑠 = 20 × 10−6 sin(𝜔𝑡 + 60°) 𝑖2 = 6 × 10−6 sin(𝜔𝑡 − 30°)

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