An electronic device and a method of fabricating an electronic device are disclosed. The device includes a body of semiconductor material, and a conductive material defining at least three conducting contacts to form respective terminals. The semiconductor material and the conducting contacts overlap at least partially to define the device, so that the electrical characteristics of the device between any pair of terminals correspond to those of a varistor. The body of semiconductor material may be a layer deposited by printing or coating. The varistor characteristics between each pair of terminals enable switching of an electrical current between one terminal and any two other terminals in such a manner that when there is a positive current into a first terminal, there is a negligible current through a second terminal at which a positive potential is applied and a positive current out of a third terminal which is held at a negative potential with respect to the second terminal. When there is a negative current outwards of the first terminal, there is a positive current into the second terminal and a negligible current through the third terminal.