OHW 30 - terry (ect328) oldhomework 30 Turner (59130) 1...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: terry (ect328) oldhomework 30 Turner (59130) 1 This print-out should have 12 questions. Multiple-choice 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 16 V and 5 A respectively, and an output current of 0 . 7 A. If there are 1397 turns turns on the sec- ondary side of the transformer, how many turns are on the primary side? Correct answer: 195 . 58 turns. Explanation: Let : n s = 1397 turns , I p = 5 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 = (1397 turns) . 7 A 5 A = 195 . 58 turns . 002 10.0 points An ideal transformer shown in the figure below has a primary with 20 turns and sec- ondary with 8 turns. The load resistor is 72 . The source voltage is 98 . 7 V rms . 98 . 7 V rms R S 20turns 8turns 72 If a voltmeter across the load measures 18 . 3 V rms , what is the source resistance R S ? Correct answer: 520 . 82 . Explanation: Let : R S = Source Resistor , R L = 72 , N 1 = 20 turns , N 2 = 8 turns , N 1 N 2 = 5 2 , and E = 98 . 7 V rms . The rms voltage across the transformer pri- mary is V 1 = N 1 N 2 V 2 , (1) using V 1 from Eq. 1, the source voltage is V S = V R S + V 1 = I 1 R S + N 1 N 2 V 2 . (2) The secondary current is I 2 = V 2 R L . (3) The primary current, in terms of the sec- ondary current, is given by I 1 = I 2 N 2 N 1 . (4) Substituting the expression for I 2 from Eq....
View Full Document

Page1 / 4

OHW 30 - terry (ect328) oldhomework 30 Turner (59130) 1...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online