With high electrode resistance comes the impact of capacitance
coupling and electrical noise (Figure 11). The lead wire exiting the
measuring electrode is prone to picking up spurious electrical
signals—an effect known as hand capacitance. Similar to
extending a radio antenna for pulling in distant stations, the
longer the electrode lead wire length, the more prone the
electrode is to picking up interference. In the case of hand
capacitance, merely waving a hand next to the cable will cause
the measuring instrument display to change erratically.