Some embodiments include electronic devices having two capacitors connected in series. The two capacitors share a common electrode. One of the capacitors includes a region of a semiconductor substrate and a dielectric between such region and the common electrode. The other of the capacitors includes a second electrode and ion conductive material between the second electrode and the common electrode. At least one of the first and second electrodes has an electrochemically active surface directly against the ion conductive material. Some embodiments include memory cells having two capacitors connected in series, and some embodiments include memory arrays containing such memory cells.