What is parasitic resistance / capacitance?

Hi, need some help in finding out what is this exactly.

when i was actually designing a PCB board, someone told me that the tracks of a circuit shouldn't be too close(0.5mm apart). And this has something to do with parasitic resistance / capacitance. But i have no idea what it is.

I already searched using google but i can't find any definition on it? Can someone please explain what is parasitic resistance / capacitance and how does it actually occur?

thanks alot in advance

A capacitor is two conductors seperated by an insulator - which is EXACTLY what two nearby PCB tracks are. This is only likely to be a problem under certain circumstances, and normally only at very high frequencies.

As you haven't mentioned what your circuit is?, I can't suggest if it might be a concern - but unless it's a high frequency RF circuit, it's very unlikely.

Parasitic resistance/capacitance is any that you don't want.