Voltage Divider for Inductive Proximity Sensor

[Redox_07]

Hi LabView Board,

Please refer to the image shared on : https://forums.ni.com/t5/Multifunction-DAQ/Inductive-proximity-sensor-reading/m-p/2616659#M79464 

I am reposting as a fresh question.

I was considering a similar implementation for my circuit using the proximity sensor. However, given with my basics of the voltage divider and considering the following:

Vi as the input voltage

R1, R2 as divider resistances

V1, V2 respective voltage drops

then, V1= Vi * (R1/(R1+R2)) and V2 = Vi * (R2/(R1+R2)).

the circuit configuration marked as the solution has R1 & R2 indicated as 1000 Ohm and 1500 Ohm. The output across R2 is given input to 0-10V range DAQ.

Now calculating V2 as per given values and above formula:

V2 = Vi * (R2/(R1+R2)) = 24 * (1500/(1000+1500)) = 24 * 1500 / 2500 = 14.4 V

definitely 14.4 V shouldn't be the input to the DAQ!

Higher resistance has a higher voltage drop across it and vice versa.

then why DAQ is connected to higher resistance R2?

Kindly clarify.

[Redox_07]

hi,

I was considering similar implementation for my circuit using proximity sensor. However given with my basics of voltage divider and considering the following:

Vi as input voltage

R1, R2 as divider resistances

V1, V2 respective voltage drops

then, V1= Vi * (R1/(R1+R2)) and V2 = Vi * (R2/(R1+R2)).

the circuit configuration marked as solution has R1 & R2 indicated as 1000 Ohm and 1500 Ohm. The output across R2 is given input to 0-10V range DAQ.

Now calculating V2 as per given values and above formula:

V2 = Vi * (R2/(R1+R2)) = 24 * (1500/(1000+1500)) = 24 * 1500 / 2500 = 14.4 V

definitely 14.4 V shouldn't be the input to the DAQ! Kindly clarify

[GerdW · Accepted solution]

Hi Redox,

when you swap the resistance values to R1=1500 Ohm and R2=1000 Ohm then everything looks nice.

Probably a simple glitch by Lynn…

[Redox_07]

I had a headache wondering why why why? thanks to you.

[GerdW · Accepted solution]

Hi Redox,

as an engineer (to be) you should be able to apply simple voltage divider (Kirchhoff's rules) on your own without getting headache…