unconnected-component

Remedy ¶

Wire the part into the circuit it belongs to, or delete it from the schematic if it is left over from an earlier revision. Placed and unwired is neither.

What it means ¶

A component has no pin on any net at all. It is placed but wired to nothing.

Why engineers want it ¶

Parts get dropped onto a sheet and left unwired during a work in progress, or a block gets deleted and one part survives. The part then ships in the BOM and gets placed on the board while doing nothing.

Impact ¶

Either a real missing connection (the part was supposed to be in the circuit) or wasted cost and board area. Both are worth surfacing.

Parts with no pins ¶

A mounting hole, a logo or a module’s assembly symbol declares no pins, so “none of its pins is on a net” is true of it and says nothing. Such a part is not considered (agni issue 937). Sometimes a part’s read carries no pin list at all, as a hand-built or pin-less netlist gives. That part still fails when nothing connects to it, because its pins are unknown rather than absent.

Section-aware ¶

Connections key on ref_des, and the IR groups all of a physical part’s sections under one ref_des (WS1-001), so a part counts as connected if any section’s pin is on a net. A multi-gate IC with one gate wired is connected.

Query structure ¶

select the components not present in the connected-ref set.

select C in components where ref_des(C) != "" and not on_net(C)

Reads: on_net (the connected-ref projection). Tier R (a traverse of every net’s members builds the set, and the select tests against it).