³Ô¹Ïtv / ENGINEERING NOTEEvidence sequence: PCB Thermal Design Principles1Series elementSame heat passes through each counted element.2Parallel branchesBoth branches share the same two temperature nodes.3Time boundarySteady state distinguished from transient or cycling operation.4ValidationEquivalent source, geometry and measurement locations for A/B comparisons.Conceptual drawing. Not to scale; not manufacturing or compliance evidence.