9030.90.66.00 - Of instruments and apparatus of subheading 9030.40 or 9030.82

This HTS category, 9030.90.66.00, specifically covers printed circuit assemblies that are parts or accessories for instruments and apparatus classified under subheadings 9030.40 or 9030.82. These subheadings generally encompass oscilloscopes, spectrum analyzers, and other instruments designed for measuring or checking electrical quantities, as well as devices for measuring or detecting ionizing radiation. Therefore, this classification is for the electronic boards and components within such sophisticated measuring and testing equipment.

Distinction from its sibling category, 9030.90.68.00 ("Other"), is crucial. While 9030.90.66.00 is exclusively for printed circuit assemblies, the "Other" sibling category is a residual classification for all other parts and accessories for instruments under heading 9030 that are not otherwise specified. This means if a part is not a printed circuit assembly, or if it is a printed circuit assembly not intended for the specific instruments in 9030.40 or 9030.82, it would likely fall under 9030.90.68.00.

As a leaf node, this classification does not have further subcategories. Therefore, the focus remains on accurately identifying printed circuit assemblies that serve as components for the particular types of electrical measuring and radiation detection instruments referenced in the description. Classification within this code relies on the intended end-use and the specific functionality of the printed circuit assembly within the broader instrument, rather than its material composition or manufacturing process.