Composite materials having conductive properties are described for use in testing circuits and in manufacturing electrical switches. The composite materials described, when in an unstressed state, generally behave as insulators. However, when sufficient mechanical pressure is applied to portions of the composite materials, the portions to which the mechanical pressure is applied become increasingly conductive. Methods for testing a PCB using composite material switches are also disclosed. A sheet that includes a composite material may be used to test electrical functionality of various regions on a PCB by way of local pressure application. The sheet may be easily applied to and removed from the PCB. Additionally, in forming an electrical switch, a voltage applied to one or more actuating elements may be used to provide mechanical pressure to a composite material that is disposed between two conductive members. Application of a sufficient voltage allows for portions of the composite material to transition from an insulator to a conductor for providing an electrical pathway.