{"product_id":"signal-conditioner-for-piezoelectric-sensors","title":"Signal Conditioner for Piezoelectric Sensors","description":"\u003cp\u003eThis is a simple signal conditioner circuit for\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003ePiezoelectric\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003esensors. The circuit converts the input charge to voltage and the level shifts to the A\u003cstrong\u003eD\u003c\/strong\u003eC input range of\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003e0.1 V to 2.4 V\u003c\/strong\u003e. The circuit is built using\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003eAD8608\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003eOPAMP from Analog devices. Piezoelectric elements are used to construct transducers for a vast number of different applications. Piezoelectric materials generate an electrical charge in response to mechanical movement, or vice versa, produce mechanical movement in response to electrical input. The board shown here is suitable for the\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003eKistler type 8002K\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003esensor. The K8002K is a high-precision accelerometer for shock and vibration measurements.\u003c\/p\u003e\n\u003cp\u003ePiezoelectric elements are commonly used for the measurement of\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003eacceleration\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003eand\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003evibration.\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003eHere, the piezoelectric crystal is used in conjunction with a seismic mass m. If the mass is subjected to acceleration\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003ea\u003c\/strong\u003e, then there is a resulting inertial force\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003eF = m × a\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003eacting on the seismic mass and the piezoelectric crystal. This results in the crystal acquiring a charge\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003eq = d × F\u003c\/strong\u003e, where d (measured in Coulombs\/Newton, C\/N) is the crystal charge sensitivity to force.\u003c\/p\u003e\n\u003cp\u003eThe first stage of the signal conditioning circuit is a\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003echarge amplifier\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003e(U1A and capacitor C2), The output of the circuit is shifted to handle\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003ebipolar\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003einput signals (for example, vibration measurements). The zero of the circuit is shifted to the middle of the input range of the ADC, using a reference of\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003e1.25 V\u003c\/strong\u003e. The second stage of the signal conditioning circuit is a non-inverting amplifier which provides the output.\u003c\/p\u003e\n\u003cp\u003eReference Voltage approx.\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003e1.25V\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003eis generated through resistor dividers R9 and R11. An optional chip U2\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003eTLV431\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003eSOT23-3 can be used for accurate reference voltage. The circuit is from the Analog Device’s Application Note. Considering the tolerances of the parts, the minimum output voltage (low limit of the range) is set to\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003e100 mV\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003eto allow for a safety margin. The upper limit of the output range is set to\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003e2.4 V\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003eto give 100 mV headroom for the positive swing at the ADC input. Therefore, the nominal output voltage range of the input op amp is\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003e0.1 V to 2.4 V\u003c\/strong\u003e.\u003c\/p\u003e\n\u003ch3\u003eFeatures\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eSupply 3.3V DC\u003c\/li\u003e\n\u003cli\u003eOutput 100mV to 2.4V\u003c\/li\u003e\n\u003cli\u003eOn Board Optional Reference Chip\u003c\/li\u003e\n\u003cli\u003eOn Board Power LED\u003c\/li\u003e\n\u003cli\u003ePCB Dimensions 26.35 x 14.92 mm\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"dotfry","offers":[{"title":"Default Title","offer_id":47221739684012,"sku":"S135","price":12.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0757\/6436\/7532\/files\/S135A.jpg?v=1789548888","url":"https:\/\/dotfry.com\/products\/signal-conditioner-for-piezoelectric-sensors","provider":"dotfry","version":"1.0","type":"link"}