Need some help with basic electronics math

[The_Eric]

Hey guys I'm trying to set the tps voltage on my snowmobile. The spec calls for you to apply a 5vdc reference and then make adjustments as needed. Well my pieced together power supply puts out 5.15vdc. How do I account for that in the final adjustment?

Here is a diagram and resistance values to show what I'm working with

 

[Virtus_Probi]

I assume you are adjusting a pot to make VTA be a certain voltage?
Make the target 3% higher...say if they are asking for VTA=1V with VC=5V, just shoot for 1.03V with VC=5.15V.
You're only dealing with a linear component, nothing nonlinear will happen.

 

[tcp71]

With a 3% deviation, you can decide if it really matters. I would suspect 3% error and non-linearity in the potentiometer anyway. If you are looking for specific values, simply multiply them by 1.03 to get the value that you should be seeing on your meter compared to the expected value, when using 5.15V as your input.

 

[The_Eric]

The spec is 4.1VDC at WOT, so I would need to set it for 4.22VDC?

 

[Virtus_Probi]

Originally Posted by The_Eric
The spec is 4.1VDC at WOT, so I would need to set it for 4.22VDC?

Yup!

 

[The_Eric]

Awesome - thank you guys!

 

[Virtus_Probi]

Originally Posted by The_Eric
Awesome - thank you guys!

 

[philipp10]

5.15/5.0 = 1.03. Take the 1.03 x 4.1 = 4.22.