A method of electrical device characterization comprises: providing an array of electrical devices arranged in rows and columns, wherein each electrical device has a first terminal, a second terminal and a third terminal; clamping a first voltage at a first terminal of a selected electrical device via a first buffer or an first external voltage source; clamping a second voltage at a second terminal of a selected electrical device via a second buffer or a second external voltage source; controlling a third buffer to couple the third terminal of the selected electrical device to a first terminal or a second terminal of at least one non-selected column of electrical devices; and deriving a characterization result via the third terminal of the selected electrical device; wherein the array of electrical devices, the first buffer, the second buffer and the third buffer are on a same die or a same module.