cf kinds of several resistive sensor 1 strain

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cf. kinds of several resistive sensor 1) strain gage = changes in L &

cf. kinds of several resistive sensor 1) strain gage = changes in L & 2) force sensing resistor = changes in A. 3) thermistor = changes in T. 4) potentiometer = changes in L.

Principle of FSR F F R R R eq) A ∝ F, R ∝

Principle of FSR F F R R R eq) A ∝ F, R ∝ 1/F F

(A) R ceramic R circuit NTC (Negative Temp Coefficient) T VO VS F VS

(A) R ceramic R circuit NTC (Negative Temp Coefficient) T VO VS F VS T ☜ not linear

(B) (C) bridge circuit (D) linearriation R linear range

(B) (C) bridge circuit (D) linearriation R linear range

A x Most capacitor sensors are based on changes in x.

A x Most capacitor sensors are based on changes in x.

1. Self inductance 2. Mutual inductance 3. Differential inductance ( kinds of Inductance sensor

1. Self inductance 2. Mutual inductance 3. Differential inductance ( kinds of Inductance sensor ) F ac LVDT (Linear Variable Differential Transformer. )

+D c +δ x=0 -δ -D case 1) when core is at x=0, Vcd

+D c +δ x=0 -δ -D case 1) when core is at x=0, Vcd Vfe >> t=0: 0. 01: 2; >> y 1=-sin(2*pi*t); >> y 2=+sin(2*pi*t); >> plot(t, y 1); >> hold on; >> plot(t, y 2, 'r'); >> clear;

case 2) when core is at x=+δ, Vcd Vfe Vo >> t=0: 0. 01:

case 2) when core is at x=+δ, Vcd Vfe Vo >> t=0: 0. 01: 2; >> y 1=-sin(2*pi*t); >> y 2=2*sin(2*pi*t); >> y 3=sin(2*pi*t); >> plot(t, y 1); >> hold on; >> plot(t, y 2, 'r'); >> plot(t, y 3, 'k'); case 3) when core is at x=-δ, Vcd Vfe Vo >> t=0: 0. 01: 2; >> y 1=2*sin(2*pi*t); >> y 2=+sin(2*pi*t); >> y 3=-sin(2*pi*t); >> plot(t, y 1); >> hold on; >> plot(t, y 2, 'r'); >> plot(t, y 3, 'k');

q=change, x=deflection x then i=0 piezoelectric sensor has no dc response ☞circuit 1) Pirzoelectric

q=change, x=deflection x then i=0 piezoelectric sensor has no dc response ☞circuit 1) Pirzoelectric sensor i(t)

☞circuit 2) “change amplifier” i(t) Piezoelectric sensor

☞circuit 2) “change amplifier” i(t) Piezoelectric sensor

<theory> If you plan to use the piezoelectric sensor for measuring pulse, the lowest

<theory> If you plan to use the piezoelectric sensor for measuring pulse, the lowest frequency of pulse signal is assumed to be 0. 1 Hz