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Unformatted text preview: song (shs546) – Homework 19 – weathers – (22202) 1 This printout should have 10 questions. Multiplechoice questions may continue on the next column or page – find all choices before answering. 001 10.0 points A transformer has input voltage and current of 13 V and 7 A respectively, and an output current of 0 . 7 A. If there are 1328 turns turns on the sec ondary side of the transformer, how many turns are on the primary side? Correct answer: 132 . 8 turns. Explanation: Let : n s = 1328 turns , I p = 7 A , and I s = 0 . 7 A . Energy is conserved, so P p = P s I p V p = I s V s V p V s = I s I s For the transformer V ∝ n n p n s = V p V s = I s I p n = n s I s I p = (1328 turns) . 7 A 7 A = 132 . 8 turns . 002 (part 1 of 2) 10.0 points A stepup transformer is connected to a gen erator that is delivering 147 V and 110 A. The ratio of the turns on the secondary to the turns on the primary is 955 to 1. What voltage is across the secondary? Correct answer: 140 . 385 kV. Explanation: Let : n s n p = 955 1 = 955 and V p = 147 V . V ∝ n so V s V p = n s n p The stepped up voltage in secondary is V s = V p · n s n p = (147 V) (955) · 1 kV 1000 V = 140 . 385 kV . 003 (part 2 of 2) 10.0 points What current flows in the secondary? Correct answer: 115 . 183 mA. Explanation: Let : I p = 110 A . Energy is conserved, so P p = P s I s V s = I p V p I s = I p V p V s = (110 A) (147 V) 1 . 40385 × 10 5 V · 10 3 mA 1 A = 115 . 183 mA . 004 10.0 points Consider an audio amplifier with an output impedance of 538 Ω and a speaker that has an input impedance of 23 Ω. A circuit replicating this is shown in the figure below....
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 Spring '00
 Littler
 Current, Work, Alternating Current, Trigraph, Input impedance, Impedance matching

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