The "Arduino Based Autoranging AC-DC Voltmeter with TRMS" from:
https://simple-circuit.com/arduino-autoranging-ac-dc-voltmeter-with-trms/
works fine in their video, I breadboard it and measured a huge error as below:
why? the component error?
Thanks for help.
Adam

 

hi,
Have you used exactly the same component values and tolerances and also the Vref voltage.?

Do you have a photo shot to post.?
E

 

hi,
Have you used exactly the same component values and tolerances and also the Vref voltage.?

Do you have a photo shot to post.?
E

Thanks.
I used just the parts I have, but all right parts number as the picture.
L knew there are large error on the components, just wonder if this is the only reason.
the Vref voltage I measured is 2.1V.