Fake electrolytic capacitor
With the rise of demand for more affordable and sophisticated consumer electronics, the end product is not the only thing being copied or faked, the electronic component market is seeing an huge increase in counterfeit and fake components.
I ran across this photo somewhere on the web. It's about an electronic component that is found in just about every electronic device: the capacitor. Technically this is a real electrolytic capacitor, but to the buyer's surprise, this capacitor does not have the capacitance and voltage as rated on the label. Imagine his shock when he actually opened the capacitor to see a much smaller capacitor inside with inferior capacitance! It's just like a Russian doll.
For those who are not familiar with electrolytic capacitors. They are generally used to store and filter electricity. They can be used to store energy temporarily and release in a very short time - such as the ones used to power a camera's flashbulb. They are also often used in electronic power supply, circuit, etc to convert alternate current to direct current, or to maintain a steady waveform of electricity to other components. The capacitor has two main measurements: voltage in volt, and capacitance in farad. Because one farad is a large unit, the more common unit is micro-farad or uF.
The unwitting buyer of this capacitor thought he purchased a 50V 6800uf when in reality it has only a 35v 2200uf capacitor inside the empty can! This is completely unsuitable for any applications requiring the rating outside. If it is used, it will quickly fail. As a rule of thumb, the replacement capacitor should have the same or higher voltage, same or higher capacitance, but never lower ones. When this is actually used in the circuit, it may function briefly and eventually the excessive pressure created by the higher voltage and current draw from the circuit would cause the top of the capacitor to swell and leak or blow up. It is usually not a dangerous thing when capacitors fail though, but it would cause the circuit to malfunction.
Now, why would people take the time to put a real capacitor inside a fake one and for some extra cents is difficult to understand. It is unlikely they can sell this in large volume as manufacturers would conduct quality testing before using them, in small batches, the profit margin while good, the amount is very slim. A 50v 6800uf capacitor cost around $2 retail, and a 35v 2200uf cost around 60 to 80 cents. The seller of this fake capacitor must hope to sell thousands of these before it's worthwhile.
The capacitor is a basic component. While most counterfeit electronic parts are basic electronic components, complex products such as microprocessor, microcontroller, transistor IC are also frequently counterfeited. So beware, not only a camera, cell phone or DVD player can be faked, also the things inside are not such a certainty anymore.