Pressure DetectorsPRESSURE DETECTION CIRCUITRYOther resistance-type transducers combine a bellows or a bourdon tube with a variable resistor,as shown in Figure 6. As pressure changes, the bellows will either expand or contract. Thisexpansion and contraction causes the attached slider to move along the slidewire, increasing ordecreasing the resistance, and thereby indicating an increase or decrease in pressure.Figure 6 Bellows Resistance TransducerInductance-TypeTransducersFigure 7 Inductance-Type Pressure Transducer CoilThe inductance-type transducer consists ofthree parts: a coil, a movable magnetic core,and a pressure sensing element. The elementis attached to the core, and, as pressure varies,the element causes the core to move insidethe coil. An AC voltage is applied to thecoil, and, as the core moves, the inductance ofthe coil changes. The current through the coilwill increase as the inductance decreases. Forincreased sensitivity, the coil can be separatedinto two coils by utilizing a center tap, asshown in Figure 7. As the core moves withinthe coils, the inductance of one coil willincrease, while the other will decrease.Rev. 0 Page 9 IC-02
Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business
