For hearing aid

85.06 - Primary cells and primary batteries (+). 8506.10 8506.30 8506.40 8506.50 - Manganese dioxide - Mercuric oxide - Silver oxide - Lithium - Other primary cells and primary batteries 8506.90 - Parts 8506.80 These generate electrical energy by means of chemical reactions. A primary cell consists basicall of a container holding an alkaline or a non-alkaline electrolyte (e.g., potassium or sodium hy oxide, ammonium chloride or a mixture of lithium chloride, ammonium chloride, zinc chloride and water) in which two electrodes are immersed. The anode is generally of zinc, magnesium or of lithium and the cathode (depolarising electrode) is, for example, of manganese dioxide (mixed with carbon powder , of mercuric oxide or of silver oxide. In lithium rirnary cells, the anode is of lithum an the cathode is, for example, of thionyl chloride, o sulphur dioxide, manganese dioxide or of iron sulphide. A nonaqueous electrolyte is used because of the solubility and reactivity of lithium in aqueous solutions. In air-zinc rimary cells, an alkaline or neutral electrolyte is generally used. The zinc is used as the ano e, oxygen diffuses into the cell and is used as the cathode. Each electrode is provided with a terminal or other arrangement for connection to an external circuit. The principal characteristic of a primary cell is that it is not readily or efficiently recharged. & d F 2' Primary cells are used for supplyin current for a number of purposes (for bells, telephones, hearing aids, cameras, watches, ca culators, heart a c e d e r s , radios, toys, portable lamps, electric prods for cattle, etc.). Cells may be oupe together in batteries, either in series or in parallel or a combination of both. Cells and atteries remain classified here irrespective of the use for which the are intended (e.g., standard cells for laboratory work producmg a constant known voltage fa1 in the heading). P f T a The various types of cells include : (1) Wet cells, in which the electrolyte is a liquid, and is not restrained from flowing. Wet cells are therefore sensitive to orientation. (2) Dry cells, in which the electrolyte is imrnobilised in absorbent materials or gels (e.g., mixed with a thickener such as a ar-agar or flour to form a paste). The electrolyte used may be liquid but it is restraine from flowing. Dry cells are used mainly for portabIe devices. 'f (3) Inert cells, or reserve cells or batteries to which water or all or part of the electrolyte must be added before they can be used, or in which the electrolyte must be heated to become ionically conductive. (4) Concentration cells, the electrolyte being at a different degree of concentration at each electrode. Primary cells and batteries may be manufactured to various shapes and sizes. Common types are those having a cylindrical or button shape. Certain cells (e.g., wet cells and some inert cells) are usually presented without their electrolyte, but remain classified here. This heading does not cover rechargeable cells and batteries, as these are classified in heading 85.07 as electric accumulators. PARTS regardin the classification of parts (see the General XVQ, the hea%. mg covers parts of primary cells or batteries, The heading does not cover : (a) Terminals (heading 85.36). (b) Solar cells (heading 85.41). (c) Carbon electrodes (heading 85.45). (d) Spent primary cells and spent primary batteries and waste and scrap thereof (heading 85.48). (e) Thermocouples (e.g., headings 85.03,85.48,90.33).