Circuit Technology Services Offers 4-Wire Kelvin Testing for PCB Resistance Measurement

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Circuit Technology Services Inc. (CTS), a provider of PCB testing, high-voltage testing, Kelvin testing, TDR testing, and PCB rework services for the printed circuit board industry, provides 4-wire Kelvin testing for PCB circuit resistance measurement to support the detection of high-resistance continuity failures and circuit integrity issues in printed circuit boards.

The traditional continuity test methods perform pass/fail testing at a set resistance value, which can miss defects in circuits with low resistance requirements. According to CTS, a circuit intended to have a resistance value of 0.1 ohms can still pass a traditional continuity test at resistance values up to 10 ohms, potentially resulting in performance and reliability issues.

The company’s Kelvin testing detects high-resistance continuity failures and supports verification of PCB integrity before assembly. The company notes that the process can identify defects, including via and hole wall conductivity issues, trace line imperfections causing high resistance, and surface contamination affecting contact performance.

CTS explains that 4-wire Kelvin testing, also referred to as 4-terminal sensing, measures low resistance values using two probes at each test point, including a force probe and a sense probe. According to CTS, the force probe applies a constant current while the sense probe measures voltage to generate resistance readings.

CTS also states that resistance value reports generated during Kelvin testing can support design and manufacturing processes for critical high-end products.

The company outlines its Kelvin testing capabilities as:

• Resistance range: 0.25mΩ – 1kΩ
• Accuracy: +/- 0.025 mΩ +/- 2%
• Contact pressure: 0.2 g to 5.0 g
• Minimum test pad size: 4 mil

Click here to learn more about the 4-wire Kelvin testing.