A yes b no abhavethesamepotential

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Unformatted text preview: ircuit, assume Vi and Ri are known. What is I2 ?? • We have 3 equations and 3 unknowns. I2 = I1 + I3 V1 + I1R1 ­ I3R3 + V3 = 0 V2 – I2R2 ­ I1R1 + V1 = 0 I1 I2 I3 •The solution will get very messy! Simplify: assume V2 = V3 = V V1 = 2V R1 = R3 = R R2 = 2R Calculation: Simplify Calculation: Simplify In this circuit, assume V and R are known. What is I2 ?? R 2R R 2V V V I1 I2 • We have 3 equations and 3 unknowns. I2 = I1 + I3 ­2V + I1R ­ I3R + V = 0 (outside) ­V – I2(2R) ­ I1R + 2V= 0 (top) I3 • With this simplification, you can verify: I2 = ( 1/5) V/R I1 = ( 3/5) V/R I3 = (­2/5) V/R 2V R V 2R a b R • V Follow­Up Follow­Up I1 • We know: BB I2 = ( 1/5) V/R I1 = ( 3/5) V/R I3 = (­2/5) V/R I2 I3 Suppose we short R3: What happens to Vab (voltage across R2?) (A) Vab remains the same (B) Vab changes sign (C) Vab increases (D) Vab goes to zero Vcd = +V Vbd = +V Vad = Vcd = +V R Why? Redraw: Vab = Vad – Vbd = V – V = 0 2R a 2V V b c V I1 I2 I3 d a V...
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