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Sensors(2). Dept. of Biomedical Engineering 2003200449 YOUNHO HONG. Inductive sensor. Self inductance Mutual inductance. F. x. Vs. Vo. + Vo -. Vs. Magnetic core. Inductive sensor. (3) Differential inductance (a) when core is at x=0. c. +D. a. δ. d. X=0. f. - δ. -D. e.
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Sensors(2) Dept. of Biomedical Engineering 2003200449 YOUNHO HONG
Inductive sensor • Self inductance • Mutual inductance F x Vs Vo + Vo - Vs Magnetic core
Inductive sensor (3) Differential inductance (a) when core is at x=0 c +D a δ d X=0 f -δ -D e b Vcd Vfe Vo
Inductive sensor (b) When core is at x=+δ (c) When core is at x=-δ Vcd Vfe Vfe Vcd Vo Vo
LVDT(Linear variable differential transformer) (problem 13.) (a) Skretch output signal of LVDT from 0ms to 10ms.
LVDT(Linear variable differential transformer) (b) Write the methods of finding y(t). Method 1 : Full wave Rectifier + LPF Method 2 : phase-sensitive demodulation + LPF Vo(t) FWR V(t) Vo(t)
LVDT(Linear variable differential transformer) (ploblem 14.) (a) θ=0. (b) θ=10. + LPF Vo(t)
LVDT(Linear variable differential transformer) (c) θ=45. (d) θ=90. To get rid of this effect, We need to multifly .
Piezoelectric sensor x q = kx Piezoelectric sensor has no dc response. Piezoelectric cristal charge deflection (1) X(t) Vs(t) Vo(t)
Piezoelectric sensor (2) If you plan to use the piezoelectric sensor, for measuring pulse, The lowest freq of pulse signal is assumed to be 0.1Hz. Vo(t) |H| k/c f Fc=1/2πRC