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Following an illustration of D'Arsonval movement such as the following...

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I notice that the N polarized part of the coil is connected to the positive lead and the S polarized part of the coil is connected to the negative lead. Why is the galvanometer configured this way? Does the meter always have to be configured this way?

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The orientation N and S of the movement electromagnet are determined by the direction of the current and the winding direction. This can be easily remembered using the right-hand grip rule.

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Figure 1. The right-hand grip rule: with fingers wrapped in the direction of current flow the thumb points in the direction of the field (N). Source: OneSchool.

With a little thought it can be seen that the illustration in the question is correctly drawn and that the north pole of the momement is at the top.

I notice that the N polarized part of the coil is connected to the positive lead ...

Not quite right. The N isn't "connected" - it is a result of current flow and winding direction. There is no electrical connection as the wire is insulated.

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Figure 2. Another D'Arsonval galvanometer movement diagram showing the springs. Source: Engineer's Edge

As current is increased the like poles repel introducing a turning moment which acts against a spring to give a rotation proportional to the current.

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