Top IPC subclasses
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1
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H01M
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3
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processes or means, e.g. batteries, for the direct conversion of chemical energy into electrical ene
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2
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G09B
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3
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educational or demonstration appliancesappliances for teaching, or communicating with, the blind, de
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3
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H02J
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2
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circuit arrangements or systems for supplying or distributing electric powersystems for storing elec
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