The continuous miniaturization of electronic and electromechanical devices has allowed the study of non-visible effects on macroscales, as it is the case of the behavior of microgap separated electrodes. The behavior of aluminum electrodes at atmospheric pressure appears here for a rank of separations of 1 μm to 22 μm. The Paschen curve is conventionally used to describe the behavior of electrodes. The results demonstrate that at separations smaller than 4 μm the breakdown voltage in the electrodes decays dramatically and it does not present a minimum as predicts the Paschen curve. This modification establishes critical conditions of operation in devices based on electrodes with microgap separations [1, 2].