Abstract：The voltage-current characteristics of carbon and carbon fiber reinforced silicone rubbermatrix conductive composites were tested under DC or AC voltage. The result shows that the conductive compo-sites have non-ohmic behavior with nonlinear relationship of voltage and current. The current output is not affected for small change of AC excitation frequency, but decreases significantly with the frequency increase for large change. The sample impedance decreases with the increase of frequency in different AC frequency test. Tunnel conductivity (capacitance impedance) exists simultaneously with lap joint/contacts conductivity (resistance impedance) in the conductive composites, and the tunnel current is main factor for above phenomenon. The results show that it is important to know the excitation power model during electric property test of conductive composites.
2012, Vol. 33 
