It is an object to provide a measuring apparatus and method which can easily measure an amount of a biological component such as glucose without requiring an ordinary person who is to be measured to have special knowledge and techniques. In said method, the power impulse intervals acting on the partial cathodes are selected in such a way as to overlap, thereby dispensing with the need to interrupt the drawing of power supplied by the generator. In addition, a method for testing such a circuit is disclosed. A manifold coupled to the cylinder is in fluid communication with the first chamber.