About Compact Printed Circuit Board Components

A compact printed circuit board (PCB) is an electrical circuit that is held together by a nonconductive substrate. The components of the circuit rest on the surface of the substrate.

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Defining a Compact Printed Circuit Board Component

Compact Printed Circuit Board Structure

A simple PCB consists of signal traces, a flat substrate layer, and circuit components. The signal traces, which serve as the "wiring" between the circuit components, are made of a conductive material (for example, copper). During manufacturing, the signal traces are laminated to the substrate layer, which provides the structural integrity for the overall PCB. Typically, this substrate layer is a lightweight insulated material (for example, reinforced fiberglass). The circuit components are mounted on top of the substrate at the appropriate locations along the signal traces.

A complex PCB can be double-sided or multilayer. In a double-sided PCB, there are signal traces laminated on both sides of the substrate layer. In a multilayer PCB, there is a layer of substrate between each layer of signal traces to prevent short circuits. Via holes serve as the junctions between the separate layers of signal traces. In both double-sided and multilayer PCBs, circuit components can be mounted to the top and bottom surfaces of the PCB.

Complex PCBs offer a distinct design advantage over simple PCBs—they have a smaller footprint than the simple PCBs because the circuitry is layered. In addition, you can mount circuit components on both sides of a complex PCB, whereas you can mount circuits components on only one side of a simple PCB.

Energy Transfer

When supplying power to the components on a compact PCB, a process called "joule heating" converts some of the energy passing through the signal traces to heat. The amount of heat that diffuses through the substrate layers into the ambient fluid depends on several factors, including the following:

  • Power supplied
  • Substrate material
  • Signal trace material
  • Number of substrate layers
  • Volume of signal traces in each substrate layer
  • Thickness of each substrate layer

When you define the percent volume of signal traces in a substrate layer, the app computes the volume-weighted average value of the thermal conductivity, density, and heat capacity of that layer. The app uses these values to calculate the heat transfer in the interior of the PCB and to the ambient fluid. The app assumes that the supplied power is distributed uniformly throughout the volume of the PCB.