Causes and solutions for chip resistance measurement value jumps

During the assembly and maintenance of electronic equipment,Chip resistorAs a commonly used passive component, the stability of its measured value directly affects the normal operation of the circuit. However, many engineers and technicians measure patchresistanceWe often encounter the problem of numerical jitter, which leads to judgment errors and debugging difficulties. This article will discuss in detail the reasons why chip resistor measurement values ​​jump, and provide practical solutions to help readers accurately measure and apply chip resistors.

The resistance of chip resistors is usually small or large. If the multimeter or resistance measuring instrument used is not accurate, it may easily lead to unstable readings. Some low-end instruments have large internal resistance or low sampling frequency, and the values ​​fluctuate significantly during measurement. It is recommended to use a high-precision digital multimeter or a special resistance test instrument to ensure the accuracy and stability of the measurement.

When measuring chip resistance, the quality of contact between the test probe and the resistor pin is extremely critical. If the probe contact is not firm or the contact surface is oxidized, the contact resistance will change frequently, causing the measurement value to jump. The solution is to use a spring-loaded test clip to ensure good contact between the probe and the chip resistor, and clean the contact point to remove the oxide layer before measurement.

Chip resistors are usually welded on complex circuit boards. If the resistor is not isolated from the circuit during measurement, it may be affected by parallel or series components, resulting in unstable resistance measurement. Especially for circuits with filter capacitors or diodes, the value jumps more obviously during measurement. It is recommended to remove the resistor from the circuit or disconnect the relevant wiring during measurement to ensure a single measurement object.

Fluctuations in ambient temperature and humidity will affect the resistance stability of chip resistors, especially high-precision and high-resistance resistors with large temperature coefficients. Changes in ambient temperature during measurement will cause changes in resistor resistance, which is manifested as numerical jumps. Measurements should be carried out in a constant temperature and humidity environment, or environmental factors should be compensated.

Electromagnetic interference, power supply noise or static electricity in the measurement environment will interfere with the measurement instrument and cause numerical fluctuations. Especially when measuring near high-frequency or high-power equipment, the interference is more significant. Using shielding measures, staying away from interference sources, and using measuring instruments with filtering functions can reduce the measurement value jitter.

Inferior chip resistors have uneven materials or poor welding processes, and may have defects in their internal structures, resulting in unstable resistance values. Purchasing products from regular manufacturers and ensuring that the quality of chip resistors is qualified is the fundamental guarantee for reducing measurement jitter.

Mismatching the DC measurement or AC measurement method, or the measurement speed is too fast, may lead to numerical instability. It is recommended to choose an appropriate measurement method based on the type of resistance and keep the test instrument stable during measurement to avoid jitter.

Value jitter in chip resistor measurement is a common but complex problem, involving many aspects such as instrument accuracy, contact quality, circuit environment, environmental conditions and component quality. By selecting high-precision instruments, ensuring good contact, isolating measurement components, controlling environmental factors and purchasing high-quality chip resistors, measurement value jitter can be effectively reduced and measurement accuracy improved. We hope that the analysis and suggestions in this article can help electronic engineers and technicians better solve the problems in chip resistance measurement and ensure product quality and stable performance.