Electrical conductance (G) measures how easily electricity flows between two electrodes. It is the ratio of the electrical current (I) to Voltage (V). For electricity passing between electrodes on each end of a piece of iron, for example, the conductance is constant because the metal consists of unchanging material.  Copper which is used in the wiring of electrical appliances would have a different and better conductance as it is made of a different material (ref). When the electrodes are on either side of the larynx and the metal is replaced by tissues of the neck then the conductance will change (much poorer) as  the consistency of the ‘conducting material’ changes as the mucosa of the vocal folds come together and peel apart during a vibratory cycle.  By applying a constant current (I) between the electrodes changes in conductance (G) are reflected in changes in voltage (V).  This change can be seen in changes in height of the Laryngograph waveform with time. The peak of the waveform reflects the point where there is maximum passage of current which corresonds to the point of maximum contact between the vocal folds while the trough is when the vocal folds are apart during the vibratory cycle.