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Fuel level dampening circuit not dampening


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I copied the circuit  in this thread as I have a similar range fuel level sender. 

However my range seems to be a lot smaller, about 1.4V - 2.7V. 

Also I seem to be getting 0 damping from the  cap circuit. I get immediate and wild changes in voltage that allow the fuel level to change drastically. Obviously especially at lower fuel levels. 

The level sender is 2 wires with the other being connected to ground. 

The negative of the capacitor is also connected to ground. 

I also double checked that it is wired in the right way around. Negative strip connected to ground. 

Does anyone have any suggestions? 

The sender unit measured 4-140 ohm's 

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4-140ohms with a 100ohm pull up should give you a voltage output range of about 0.19V to 2.92V, so your range of only 1.3V suggests something in your circuit is not right.  

Also the RC filter with 18Kohm and 1000uf should give a 90% rise time of about 40 seconds.

I suggest double checking the values of your components and rigging the circuit up on the bench with some jumper leads or breadboard etc.  

Video attached to show how it should work.


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Thanks for the reply and the video!

Looks like a good site. 

I will rebuild the circuit, the original wasn't built by me but it is soldered on a breadboard and as far I can tell all resistor values & capacitor are correct and the correct way around. 

But I'll build another circuit and see if it's better. If not I'll have to do some more digging. 

Thanks for the help! 

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