Fringing Field Capacitive Smart Sensor Based on PCB Technology for Measuring Water Content in Paper Pulp

<div>Oscilloscope screens showing the cycles of charge/discharge of the (a) reference capacitor <svg height="11.9087pt" id="M151" style="vertical-align:-3.2728pt" version="1.1" viewbox="-0.0498162 -8.6359 24.9415 11.9087" width="24.9415pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M645 631C614 643 545 666 457 666C215 666 23 519 23 283C23 90 158 -16 337 -16C412 -16 489 2 522 10C543 39 590 127 606 167L580 181C519 89 459 18 348 18C201 18 122 136 122 287C122 464 244 632 435 632C544 632 602 595 608 472L639 475C643 526 645 581 645 631Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,8.619,3.132)"><path d="M631 18C609 24 585 35 559 65C534 91 514 117 478 169C448 214 406 281 389 313C462 346 516 399 516 485C516 545 490 590 449 616C412 641 363 650 290 650H42V622C120 615 128 612 128 527V125C128 40 120 34 38 28V0H300V28C221 34 212 40 212 125V284H244C295 284 312 272 329 244C359 195 395 133 430 84C475 19 516 -3 592 -7C603 -8 615 -8 627 -8L631 18ZM212 316V563C212 591 215 602 223 607C231 613 248 617 277 617C352 617 423 577 423 469C423 415 407 375 368 345C343 324 310 316 260 316H212Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,14.27,3.132)"><path d="M517 162C503 123 484 88 467 68C445 42 417 34 341 34C291 34 256 34 237 47C219 59 213 81 213 128V317H308C395 317 402 311 415 240H444V431H415C403 364 398 356 307 356H213V584C213 613 215 616 246 616H322C394 616 421 609 435 587C448 566 458 544 467 502L496 506C493 557 488 625 488 650H42V622C120 616 128 612 128 523V125C128 43 120 35 29 28V0H511C520 31 540 125 546 158L517 162Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,19.439,3.132)"><path d="M493 503C489 551 484 614 483 650H43V622C120 616 128 611 128 525V126C128 40 120 34 40 28V0H312V28C221 34 213 40 213 126V307H316C407 307 412 296 424 227H453V420H424C412 355 407 346 316 346H213V584C213 613 216 616 246 616H322C398 616 419 607 436 579C449 559 455 539 464 499L493 503Z"></path></g></svg> and (b) sensor’s capacitance (in air) <span class="nowrap"><svg height="11.8174pt" id="M152" style="vertical-align:-3.1815pt" version="1.1" viewbox="-0.0498162 -8.6359 16.3097 11.8174" width="16.3097pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M645 631C614 643 545 666 457 666C215 666 23 519 23 283C23 90 158 -16 337 -16C412 -16 489 2 522 10C543 39 590 127 606 167L580 181C519 89 459 18 348 18C201 18 122 136 122 287C122 464 244 632 435 632C544 632 602 595 608 472L639 475C643 526 645 581 645 631Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,8.619,3.132)"><path d="M782 650H541L536 618L564 614C597 609 604 600 584 574C535 508 486 451 437 395C394 473 361 533 343 575C331 605 335 610 375 615L400 618L407 650H156L147 618C222 612 230 608 267 537L375 330C277 214 186 117 163 96C108 43 97 38 27 32L18 0H265L274 32L251 35C204 41 202 47 224 80C264 138 327 213 397 293L504 80C520 48 516 42 472 36L440 32L433 0H707L716 32C627 38 622 43 581 121L455 361L629 548C685 606 696 610 775 618L782 650Z"></path></g></svg>.</span></div>

Journal of Sensors

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Figure 7

Figure 7: Fringing Field Capacitive Smart Sensor Based on PCB Technology for Measuring Water Content in Paper Pulp 