| 摘要 |
<p>To test reaction of the labyrinth of the ear, it is required to set the temperature. Problems with gas or a liquid are enhanced when the eardrum is pierced and are overcome by use of a heat conducting insert which is controlled by the Pelletier effect. An element (EP) is shaped to fit within the ear and is temperature controlled from a variable frequency oscillator which delivers positive and negative signals w.r.t. earth potential. The oscillator drives power stages via a current matching circuit and the power stages drive the Pelletier element. When a current is applied, the respective element faces become warm and cold and are reversed when the current is reversed. The current is controlled by potentiometers (Pa, Pb) in the power stages to control the positive and negative current supply. A galvanometer dial indicates the temperature.</p> |
