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Author Topic: Measuring Kilo to Mega Ohm sensors  (Read 646 times)
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I am newbie here and looking for some help in circuit schematics to measure sensors. The baseline resistance of the sensors are 100k-100MOhms and the resistance of the sensors can vary in the same distance, for example, sensor with 10MOhm baseline resistance can exhibit a change up to 90% of its baseline. The readout of the resistance should pass to a computer using Arduino. The working voltage of the sensor is 1V.
Any recommendations for such circuit ?


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You may consider a R->frequency or period converter (with help of a jfet or mosfet op-amp) and do measure the frequency or period with arduino.
See for example below - the period changes from ~1ms (100k) to ~650ms (100Meg). Do measure the period and make some calcs.
Mind the measuring a 100Meg large resistor requires a special construction.. smiley-wink
The voltage on the sensor (Rx) is up to 3.7V (see the fourth picture).

* 100k.jpg (55.02 KB, 732x624 - viewed 21 times.)

* 10meg.jpg (58.23 KB, 832x637 - viewed 19 times.)

* 100meg.jpg (51.35 KB, 705x624 - viewed 14 times.)

* 10megVoltage.jpg (61.97 KB, 753x603 - viewed 19 times.)
« Last Edit: April 22, 2013, 03:31:17 pm by pito » Logged

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