Breakdown behaviour of sub-millimetre air gaps under alternating voltage

Experimental results leading to breakdown voltage (BDV) measurements conducted with blade-blade, hemisphere-hemisphere and needle-plane electrode configuration in air at STP have been reported in this paper. The applied voltage was 50Hz AC, the electrode material effect on the BDV´s was studied in the needle-plane configuration by changing the plane electrode material. Electric field plots for various electrode configurations have been obtained by FEM software package. The results indicate that the overall breakdown strength of the gap in the 100 μm to 1000 μm gap range shows a marginal increase up to 400 μm and increases as we approach 100 μm irrespective of the geometry. The variations in the spread as we approach lower limit of 100 μm is attributed to the electrode configuration and/or electrode material. Further work is in progress to study the pre-breakdown behavior. The results are expected to impact MEMS technology.