Chinese Products, Not What They Seem
December 8th, 2007
This is a picture of a capacitor from a Chinese company, after being cut open. Inside, it is just a small capacitor. There are two problems with this. First, capacitors are rated with two values: Working Voltage and Capacitance. The most important is the working voltage. On the large cap, it is listed as 50V. Notice the smaller cap is 35V. When a capacitor is submitted to over voltage for a long period of time, the dielectrics (the insulator between the two sides of the capacitor) in the capacitor break down and it explodes. Yee-haw. The capacity issue is a little less troubling. You bought 6800uF, but were only given 2200uF. You got a capacitor that is 1/3 of what you thought it was. These are most commonly used in power supply filters and the device it is used in will be subject to the power line frequency hum, do to poor filtering. The business model on the company is genius. By capacitors, put them in a pretty case, sell for more money. A quick search shown retail cost of the small capacitor at about $1.50. The large one, near $3.00. Genius. Until power supply capacitors start exploding.