Frequent Blunders Encountered in Individual Parts of Systems
In the world of electronics, the reliability of components is crucial for the performance and longevity of devices. A closer look at capacitors, resistors, and inductors reveals common causes of failure due to mechanical, thermal, electrical, and environmental stresses.
Capacitors, a vital component in electronic circuits, often succumb to heat, age, and electrical stress. Over time, these factors can degrade the dielectric materials, leading to diminished performance or complete failure. Overvoltage conditions or electrical overstress can also cause internal damage or short circuits.
Resistors, another essential component, can fail due to electrical overstress, which causes overheating, and mechanical stress such as solder joint fatigue or physical strain. Resistors may also degrade over time due to thermal fatigue or prolonged exposure to harsh environmental conditions.
Inductors, which play a significant role in power electronics, typically fail due to thermal stress, which can cause insulation breakdown and core damage, or mechanical stress that may lead to broken wire windings or poor connections. Electrical overstress can also cause open circuits or short circuits within the winding.
Common failure mechanisms across these components include electrical overstress (EOS) from excessive voltage or current causing damage, thermal stress and fatigue from repeated heating and cooling cycles, mechanical stress and strain such as vibrations or solder joint fatigue, and environmental factors like humidity or contamination causing corrosion or insulation breakdown.
Failure modes observed include open circuits (broken internal wiring or cracked solder joints), short circuits (internal shorts due to dielectric breakdown or contamination), and component degradation over time due to material aging.
When selecting components, it's essential to consider their properties carefully. For capacitors, factors to consider include voltage rating, value of capacitance, temperature rating, temperature coefficient, tolerance, humidity, operating cycles, maximum current, storage and packaging sizes. Resistance and tolerance are the two common criteria for selecting a resistor, while when choosing a resistor, one should consider voltage rating, resistance value, power rating, temperature coefficient, tolerance, stability, packaging, and lead style.
To mitigate these causes, consider procuring components from reputable suppliers, watching out for counterfeit parts, ensuring adequate component spacing, incorporating board protection techniques, considering thermal sensitivity, and using hermetically sealed capacitors. Understanding these causes helps in selecting proper derating, robust design, and testing methods to enhance reliability in electronic devices.
It's also important to remember that dirt build-up, insulation failure, and humidity can cause resistors to short circuit, and overheating in wire wound resistors can result in open windings. Shock and vibration can cause resistors to overheat, emphasizing the importance of considering all failure modes during component selection.
In summary, understanding the common causes of failure in electronic components can help in the selection of suitable components, robust design, and testing methods to enhance reliability in electronic devices. By being aware of these failure modes, engineers and designers can make informed decisions to create more reliable and durable electronic devices.
References: [1] "Reliability of Electronic Components," Electronics Tutorials, https://www.electronics-tutorials.ws/reliability/reliability.html [2] "Electronic Components: Failure Modes, Effects, and Analysis," Texas Instruments, https://www.ti.com/lit/an/slaa424/slaa424 [4] "Understanding Resistor Failure Modes," Allied Electronics, https://www.alliedelec.com/knowledge-center/blog/understanding-resistor-failure-modes [5] "Inductor Failure Modes," Vishay, https://www.vishay.com/docs/71777/inductorfailuremodes.pdf
Controlled impedance, a technology used to maintain consistent signal characteristics in high-speed printed circuit boards, may help prevent electrical overstress by ensuring proper voltage and current distribution, thereby reducing the risk of component failure.
To improve the reliability of electronic devices, technology can play a significant role by incorporating measures such as controlled impedance and choosing components carefully through sourcing from trusted suppliers, considering factors such as voltage rating, temperature rating, and tolerance.
