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Voltage Divider Board
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Please be positive and constructive with your questions and comments.

Re: Voltage Divider Board

by adafruit_support_bill on Thu Feb 23, 2017 2:25 pm

It's a bit of a trade-off between avoiding ground loops in general and avoiding ground bounce on the leds. Optical isolation as suggested is the ideal solution. But wiring as in your second diagram will probably work.

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Re: Voltage Divider Board

by dickillyes on Mon Sep 09, 2019 8:16 pm

This is a voltage divider circuit question: I have an old schematic with a divider that I need to utilize for a similar requirement and it has the two resistors coming from + and - and the ground common to the Arduino but there is another resistor between the two and the ADC. What does this do? Should it be calculated as a second divider since the other reference is the common Gnd?

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Re: Voltage Divider Board

by adafruit_support_bill on Mon Sep 09, 2019 8:21 pm

The voltage drop on the resistor leading to the ADC should be negligible, since the input impedance of the analog pin is about 100 MΩ, and the current flow will be tiny.

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Please be positive and constructive with your questions and comments.