I’m letting my friend Aris have his say again today and would be delighted if you would also support his plans. What he’s testing is sound, but it’s really hard to make a name for yourself in this age of colorful YouTube videos and dangerous TikTok half-truths. And so today we’re sharing our reach again and I’m pushing his project a little, because I think the whole thing is really important. You can only counteract the usual myths about products and their origins with really well thought-out and independent tests! But I’ll just let Aris write the whole thing himself now, because it’s a subject close to his heart…
We hear so much about Japanese capacitors and also that almost every capacitor made in China is bad. But is that true? I decided to do some testing in real conditions to find out the truth and in the near future my database will include all types of capacitors and do more than one test per model to check production batches as there can be differences! Real capacitor testing – because it’s easier said than done! In today’s electronics, capacitors are everywhere and play an important role in the lifespan of any product. Therefore, it is crucial to be able to evaluate their quality and tolerance to abuse using scientific methods that do not require long testing periods.
A capacitor is an electronic component that stores and releases electrical energy in a circuit. It consists of two conductive plates separated by an insulating material known as a dielectric. When a voltage is applied across the plates, an electric field is created which causes the capacitor to store energy. Capacitors are used in electronic circuits for various purposes, such as smoothing power supply voltages, filtering signals and timing applications. They are characterized by their capacitance, measured in farads (F).
High quality capacitors are essential for every electronic component, including of course the power supplies used by every electronic device today, not just your PCs. Typically, high-end power supplies use capacitors from Chemi-Con, while mid-range power supplies use cheaper caps from Teapo or Elite.
The voltage rating of a capacitor indicates the maximum voltage that a capacitor can safely withstand without breaking down. If this voltage rating is exceeded, this can lead to the insulation breaking down and the capacitor failing or even being damaged. When selecting a capacitor for a circuit, it is essential to choose one with a higher voltage rating than the maximum voltage the capacitor will experience in the application. This provides a safety buffer and helps to ensure that the capacitor operates reliably within its specified parameters.
Overloading a capacitor or applying a voltage above its rated voltage can lead to several undesirable consequences:
- Breakdown and damage:
Exceeding the voltage rating can cause the dielectric between the capacitor plates to breakdown. This breakdown can cause a short circuit, damage the capacitor and possibly other components in the circuit. - Reduced capacitance:
Overvoltage can change the physical and electrical properties of the capacitor, resulting in a decrease in capacitance. This change can affect the performance of the capacitor in the circuit. - Leakage current:
Overload stress can increase the leakage current across the capacitor. Leakage current flows through the dielectric, and excessive leakage current can negatively affect the performance of the capacitor. - Electrical failure:
Prolonged exposure to overload conditions can cause gradual degradation of the capacitor, ultimately leading to electrical failure. - Safety hazards:
In extreme cases, overvoltage can cause the capacitor to fail catastrophically, resulting in the release of smoke, gas or even bursting. This poses safety risks, especially in applications where the capacitor is close to other components or in an enclosed space.
So far, we know from experience that Japanese capacitors are better than Taiwanese ones and Taiwanese caps are better than Chinese ones. However, relying solely on the provided specifications, experience and rumors is not the most scientific way to judge a product. On a visit to Great Wall’s headquarters, I noticed that their R&D center conducts exhaustive capacitor tests, stressing test items to their maximum ratings to determine if the official specifications are correct.
I can’t test capacitors at 105 °C for 2,000 or 3,000 hours because I don’t have the equipment, time or money for the electricity bills. So I decided to replicate another test that GW also performs. They overload the capacitors under test until they explode to determine their tolerance to higher than rated voltage levels; this is how the quality of the dielectric is assessed. The higher quality caps will have a higher tolerance to overvoltage.
Since I wanted to see how this new experiment would go, I decided to start slowly, using equipment I already had in the lab, rather than investing in additional equipment from the beginning. This means that for now I will only test lower voltage capacitors and not bulk caps with voltage ratings of 400 V and above.
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