A circuit board typically looks like a flat, laminated "sandwich" made of conductive and insulating layers.
Here's a breakdown of its key visual characteristics:
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Shape and Size: Circuit boards come in various shapes and sizes depending on their application. They can be rectangular, circular, or even irregular.
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Color: The most common color is green, due to the solder mask applied for protection. However, circuit boards can also be red, blue, black, white, or yellow.
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Surface Features:
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Traces: These are thin, metallic lines (usually copper) that connect different components and carry electrical signals. They appear as a network of paths on the surface.
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Pads: Small, flat areas where components are soldered onto the board. They are usually circular or rectangular.
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Vias: Small holes that connect conductive layers on different sides of the board. They can be visible or hidden (buried vias).
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Components: Various electronic components like resistors, capacitors, integrated circuits (chips), and connectors are soldered onto the board. These components vary in size, shape, and color.
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Silkscreen: White or colored text and symbols printed on the board's surface to indicate component placement, polarity, or other information.
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Layer Structure: Circuit boards often have multiple layers (multilayer boards). These layers are typically not visible without specialized equipment, but they contribute to the board's thickness and complexity. These layers consist of conductive copper layers separated by insulating material. Each conductive layer has a pattern of traces, planes, and other etched features similar to wires on a flat surface.
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Material: The base material is often a fiberglass composite (like FR-4), but can also be made of other materials like CEM-1, or flexible materials like Kapton.
In summary, a circuit board is a complex network of conductive paths and electronic components mounted on an insulating substrate. Its appearance can vary greatly depending on its function and design.
