Sensor application and voltage dividers

Projects General Guidance
1

Hi all,

I am working on a project where im using a 12v sensor and connecting it to a 0-5v adc. the board with the adc im using has a 32.4k pull down resistor. I cannot modify the board

I dont know the sensors maximum output voltage, I have used it to measure up to 6.7v.

I would like to truncate the voltage from 6.7v down to 5v and adjust the transfer function. I have been doing this like so for some time:

image: Sensor 10k hosted at ImgBB — ImgBB
I am wondering what happens if i go with a voltage divider like so:

Image: Sensor vdivider hosted at ImgBB — ImgBB

I dont know why the images wont load, nor why arduino forum holds you hostage for 5 minutes between posts/edits..

2

Hi,
Welcome to the forum.

Please read the first post in any forum entitled how to use this forum.
http://forum.arduino.cc/index.php/topic,148850.0.html

Can you post a link to data/spec of your sensor.
What model Arduino are you using and why don't you use its AtoD, analog input?

Thanks.. Tom.. :slight_smile:

3

I am wondering what happens if i go with a voltage divider like so:

That is not a voltage divider, the voltage divider was in the first diagram with the 10K and 32.4K resistors.

4

Why would it not be considered a voltage divider? The grounds do tie together at the end of it all

5

im_the_new_guy:
Why would it not be considered a voltage divider? The grounds do tie together at the end of it all

Because for it to be a voltage divider as shown, you would have to reverse the input and output.

6

aarg:
Because for it to be a voltage divider as shown, you would have to reverse the input and output.

What if i move the 3.3k on the downside of the 10k?

7

If you move it to the other side of the 10K the yes it would be a voltage divider with 10K and the other resistor being 3K3 in parallel with 32K4.