How to Add Test Points on PCB: Simple Guide for Beginners

To add test points on a PCB, place small pads or vias connected to important signals or power lines for easy probe access. Use your PCB design software's test point tool or manually add pads labeled clearly on the silkscreen layer for identification.

Syntax

Adding test points involves placing pads or vias connected to key signals on your PCB layout. These pads should be accessible for probes during testing. You can use your PCB design software's test point feature or manually add pads with these parts:

• Pad size: Small enough to fit probes but large enough to solder if needed.
• Net connection: Connect the pad to the signal or power net you want to test.
• Silkscreen label: Add a clear label near the test point for easy identification.

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TestPoint(Name, Net, PadSize, Location)

Where:
- Name: Identifier for the test point (e.g., TP1)
- Net: The signal or power line connected
- PadSize: Diameter of the test pad (e.g., 1.0mm)
- Location: Coordinates on PCB layout

Example

This example shows how to add a test point named TP1 connected to the VCC net with a 1.0mm pad size at coordinates (50, 30) mm on the PCB layout.

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TestPoint("TP1", "VCC", 1.0, (50, 30))

Output

A 1.0mm diameter pad labeled 'TP1' appears at position (50,30) connected to the VCC net on the PCB layout.

Common Pitfalls

Common mistakes when adding test points include:

• Placing test points too close to other components, making probing difficult.
• Using pads that are too small for reliable probe contact.
• Not labeling test points clearly on the silkscreen layer.
• Connecting test points to nets that are not accessible or useful for testing.

Always verify test point accessibility and labeling before finalizing your PCB design.

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Wrong:
TestPoint("TP1", "GND", 0.3, (10, 10))  # Pad too small and cramped

Right:
TestPoint("TP1", "GND", 1.0, (15, 15))  # Larger pad with clear space

Quick Reference

Tip	Description
Pad Size	Use 1.0mm or larger for easy probing
Labeling	Mark test points clearly on silkscreen
Placement	Keep test points accessible and away from tight spaces
Connection	Connect to important signals or power lines
Numbering	Use sequential names like TP1, TP2 for clarity

Key Takeaways

Add test points as small pads connected to key signals for easy testing.

Label test points clearly on the silkscreen layer for identification.

Ensure test points are accessible and not crowded by other components.

Use a pad size of at least 1.0mm for reliable probe contact.

Plan test points early in the PCB design to simplify debugging.