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Topic: Voltage Divider & Voltmeter help (Read 7 times) previous topic - next topic

xl97

@runaway_pancake-

I did as your diagram outlined..and it works 'perfect'...

I even left the meter included when I hooked up the Arduino just to keep an eye-on readings.

SO goes back to..  I must be doing something wrong on the breadboard set-up?

here is a pic:



thanks for the help guys!.




dc42

Your 4k7 resistor is shorted out because you have both ends in the same row of the breadboard.
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xl97

got ya!.   :)
thanks.
I have also corrected my diagram to show my error/fix




I am now going to go back and change out the resistors to match for 8.4v input.

Thanks to everyone for your help.   :D

CrossRoads

So you've had 7.4V going into your analog pin all this time?  That's not good.
Does the chip feel warm when powered up now? If so, you likely blew the pin.
And if not, it may be partly damaged and fail on you eventually.

"is there a way I can meter my resistors? to accurately find out the values?"
Yes, just measure them with your multimeter. You have gold bands on the resistors? I think that's 10% tolerance (maybe 5%, I'm  not sure which).
If you know the actual values, you can use that in your math for more accurate results.
Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
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Runaway Pancake


I would just add: Ohmmeter your resistors out of circuit,
Never* put an ohmmeter on a live/powered circuit.

(* For your meter's sake.)
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