We investigate the characteristic relations of type-II and -III intermittencies in the presence of noise. The theoretically predicted characteristic relation is that <l> approximately exp[/epsilon/(2)] for a negative regime of epsilon and <l> approximately epsilon(-nu) for the positive regime of epsilon (1/2</=nu<1), where <l> is the average laminar length and (1+epsilon) is the slope of the local Poincaré map around the tangent point. We experimentally confirm these relations in a simple electronic circuit.