Classification follows the principal measuring apparatus when signal conditioning amplifiers have no independent function and are used only with oscilloscopes.

Signal conditioning amplifiers used solely and principally with oscilloscopes were classified under Chapter sub-heading 90.30, because classification had to follow the relevant section and chapter notes rather than broad technical descriptions. Note 2(a) of Section XVIII was treated as inapplicable, and Note 2(b) supported classification with the principal measuring apparatus where the goods had no independent function. Expert material showed the products were not audio frequency electric amplifiers under Heading 85.18 but were meant for signal conditioning in instrumentation and measurement. The department's contrary classification was rejected.

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Issues: Whether Signal Conditioning Amplifiers were classifiable under Chapter sub-heading 85.18 as audio frequency electric amplifiers or under Chapter sub-heading 90.30 as parts and accessories suitable for use solely or principally with oscilloscopes and other measuring or checking electrical quantities.

Analysis: The classification had to be determined by applying the relevant section notes and chapter notes rather than by relying only on general technical opinions. Note 2(a) of Section XVIII was held inapplicable because the goods were not specifically included in any of the headings covered by that note. The record showed that the goods had no independent function and were used solely and principally with oscilloscopes. The opinion obtained from BHEL was treated as of limited assistance because it was general in nature and did not provide a focused answer on the product in question. In contrast, the expert certificates produced by the assessee consistently stated that the goods were not audio frequency electric amplifiers and were meant for signal conditioning in instrumentation and measurement with oscilloscopes. On that basis, the goods could not be brought under Heading 85.18, which applies to audio frequency electric amplifiers used for sound perception, and Note 2(b) supported classification with the principal machine or apparatus.

Conclusion: The goods were held classifiable under Chapter sub-heading 90.30 and not under Chapter sub-heading 85.18, and the classification adopted by the department was rejected.

Ratio Decidendi: Where a product has no independent function and is used solely or principally with a particular measuring apparatus, its classification must follow the apparatus under the relevant section note, and it cannot be placed in a competing heading merely because of a broad or general description of amplifiers.

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