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PIC based high-resolution cap meter


New Member

I have changed all resistors. Now they are all 1%. The voltages are:

RA0 = 0,14V;
RA2 = 3,31V;
RA3 = 4,92V;
RB3 = 3,60V;

The comparator is not oscillating I have checked it with my oscilloscope.


Something is pulling RA0 down or it is floating.
Is RA0 connected to R5 and C2?
If connected, check any shorts from C2 to gnd.
If no shorts, C2 might be faulty.


Well-Known Member
Most Helpful Member
I have checked again pcb and now it works. Thanks at all for your support.
I appreciate you checking to let us know it works but is there any reason it started working? Nobody will laugh at you if it was a dumb mistake - we'll just laugh at our old memories of the time we made the same (or similar) mistake.


New Member
I'm sorry, you're right. I made the PCB with my cnc in this way:

Perhaps there was a bit of Copper between two tracks.

Regards Massimo.

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