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I need to make 9 voltage dividers in order to connect 9 resistive sensors to the analog inputs of an Arduino board. I was tempted to use a 10K resistor network to individually ground the inputs but then I wondered whether this would in any way affect the sensitivity of the measurements or generate interferences between channels... Any advice ? Many thanks

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  • \$\begingroup\$ The network is just multiple ones in one package, if the schematic is the same, why would them being in one package be any different? \$\endgroup\$ – PlasmaHH Oct 24 '18 at 12:48
  • \$\begingroup\$ Generally no, but it depends on the signal levels and frequencies you're working with, and at that point you'd also be worried about PCB layout effects and things like that. If the network is a SIP style, then the common terminal is basically a stub so the far-end resistor would see higher parasitic inductance, but again this is only an issue at higher frequencies. If it worries you get an isolated resistor network and tie the other ends to a good ground plane. \$\endgroup\$ – isdi Oct 24 '18 at 12:53
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  1. Ask a product rep to clarify, if these dividers can be cascaded. https://www.maximintegrated.com/en/products/analog/data-converters/digital-potentiometers/MAX5490.html; and then use precision reference + buffer to create the voltage that will be divided down.
  2. Also, you need opamp buffers; cannot connect individual references directly to sensor reference pin.
  3. Explore putting separate (or multiple banks of) voltage references if it is a high precision application. I doubt that you would want to do so as you need quite a few.

I was tempted to use a 10K resistor network to individually ground the inputs but then I wondered whether this would in any way affect the sensitivity of the measurements or generate interferences between channels

A schematic would explain this clause better.

I hope it helps.

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  • \$\begingroup\$ thanks Ahmed. The schematic is pretty much what's explained here : learn.sparkfun.com/tutorials/… with 9 sensors. \$\endgroup\$ – Matt Oct 24 '18 at 15:24
  • \$\begingroup\$ I don't understand your point n2: why would I need opamp buffer ? \$\endgroup\$ – Matt Oct 24 '18 at 15:28
  • \$\begingroup\$ Opamp has infinite input impedance (theoretically). It does not load the divider network or the reference IC. Driving the divider/sensor pin with Arduino 5V supply would cause continuous glitching due to the supply current. analog.com/en/analog-dialogue/articles/… \$\endgroup\$ – user202176 Oct 24 '18 at 16:35

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