Differences Between ac and dc Determinations of Germanium Thermometer Resistances

The resistances of several germanium thermometers are found to differ for ac and dc measurements. At 300 K, these differences are frequency independent from roughly 5 to 103 Hz. The ac resistances always are smaller, and the approximate temperature differences (Tdc − Tac) vary from 100 mk at 77 K to 0.2 mK below 17 K.