| > Because how is the core logic supposed to figure out how much the clock frequency changed It is frequent for such logic circuits to use clock generators made with a so-called ring oscillator, i.e. with a chain of inverters containing an odd number of them, which is connected in a loop. The clock period will be a multiple of the delay through a logic inverter. In this case the actual clock frequency tracks exactly all changes in the permissible clock frequency, regardless of their causes, including temperature and mechanical deformation. > As the capacitor rolls up into a cylinder shape, the copper-air-copper capacitor has the dielectric (air) get thinner-and-thinner. I am not sure which is the copper-air-copper capacitor to which you refer. On a PCB, there are parasitic copper-air-copper capacitors between traces, but they have very little influence on clock frequencies. On a normal integrated circuit, there is no air. The metal layers are separated by insulator layers and the top metal is covered by a passivation layer. This flexible circuit should also be covered by some passivation layer. Replacing in your argument the copper-air-copper capacitor with a copper-insulator-copper capacitor, any circuit has two kinds of capacitors, those that are made intentionally, with two overlapped metal electrodes and a very thin insulator layer between them, and the parasitic capacitors that exist between any metal traces. Your argument is valid for the parasitic capacitors, because the distance between traces will vary with bending and some parasitic capacitors will become larger, while others will become smaller. The effect of each of the parasitic capacitors on the permissible clock frequency is small and the global effect of all parasitic capacitors is unpredictable without a concrete circuit layout, because their changes with the bending may compensate each other. For an intentional capacitor, the effect mentioned by you also exists, but in most technologies for integrated circuits the thickness of the insulator of the capacitors is very small in comparison with the lengths and widths of the electrodes. In this case only a very small part of the electromagnetic field is outside the internal space of the capacitor and its influence on the value of the capacitance is negligible. Perhaps the capacitors made with this flexible technology are not as thin in comparison with their area as in other technologies, in which case the effect mentioned by you could be measurable, but I doubt it. |