In the drawings of a patent specification, it is generally required that the same parts in different drawings be given the same reference signs.
In the same picture, it is best to distinguish the same components, otherwise the instructions cannot accurately describe them. For example, ammeter 1 and ammeter 2 are both used as 1. How to describe them? Of course, if the examiner doesn't point it out, you can ignore it. If he points it out, just change the mark to a different one. It's not a substantial defect, so don't worry!
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