I have seen the equation $V = \frac {V_0}{K}$, but also the equation $U=\frac{1}{2}CV^2$. The values of C and V increase in the same linear ratio with $K$ (because $C=KC_0$). However, as the energy is proportional to $C$ and $V^2$, the energy stored by the capacitor actually DECREASES with the employment of a dielectric.
Am I correct in this interpretation? Do I take it that merely knowing the capacitance is NOT enough to compute the energy stored - I must also know this about it's construction?
(I think this may explain the problem with one of my electronics projects in the past. I see nothing to prevent two of the same capacitors from having a different energy store!)
Is it appropriate to summarize anything else one should be worried about when substituting capacitors?