However, they are still useful for a variety of measurements. If you place a custom pad as a test point, it takes up a small amount of space in the layout. Typical pads or via test points are not ideal for all circuits and devices, as they might distort signal behavior at extremely high edge rates and frequencies. This is a good idea if you suspect a component pad will not be accessible with a probe after assembly, or if you want to keep track of your test points directly in your schematic. The other option is to create custom test points in your schematic and import them into your layout. A pad on an existing component or a specific via in an existing layout can be assigned as a test point. They can also be used to inject signals into a circuit. These points are used to monitor voltage, current, and/or signal behavior in specific circuits. Very simply, a PCB test point is an electrical pad or via that can be probed during an ICT. You can then easily place your test point symbol and footprint around your board using the schematic and layout editors. However, you can create your own test point schematic symbol and footprint data for use in your board using the CAD tools in Altium Designer. Depending on your layout and components, your fabricator may not be able to reach existing pads on every critical component during an in-circuit test (ICT). You might rely on your manufacturer to assign test points, but for critical circuit blocks, you should consider placing these yourself. Some basic test fixtures and testing points should be indicated in your schematic and your PCB layout, especially when they are critical for evaluating board functionality. Bare board testing is like a moment of truth, where your fabricator and your design team determines whether a board passes inspection.
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