Re: What is the value of capacitance between a two layer PCB
Capacitence depends on the dielectric and plate size, for your problem your plate sizes will be the pcb's L x W - removed foil. dielectric is the material and space between both foils. Most basic circuit analysis books have the basic formulas to determine capacitence.
To answer other question, it's effects? I think it is best to answer this way.
1. At low frequencies - there shouldn't be too much problem however...
2. At high frequencies - there could be significant problems.
in the earlier days, RF designers would space the foil a certain distance next to another to transfer the signal from one foil to another with coils. the capacitence was built into the board.
if strain capacitence (stray) this is usually not good, the idea the capacitor blocks one thing and passes another (usually block DC and pass AC).
the best way to explain is to think of a tube(valve) the distance between the plate and grids were called inter-electrode capacitence. this capacitence effected the tube at higher frequiencies. - some problems, parasitic oscillations, passing frequiences out of expected range etc...
I was taught to keep these capacitences to a complete minimum.
finally, I think the values you asked are around the pico values(very small).
the valuse range to the RF and higher frequiences.
I hope this helps, this is good question and I'm sure many good members will add more to your knowledge on the subject.
wa