In the actual use of high-voltage capacitors, engineers often want to use a larger capacity capacitor instead of a smaller capacity. For example, a 30KV602K is used instead of six 30KV102Ks. Thus, six capacitors are used. Now one is fixed. And in terms of cost, it may be more economical. However, in actual use, the following may occur:
One of our foreign customers is producing X-ray equipment, that is, X-ray machine. They need to use 30KV102K high-voltage ceramic capacitor. In order to not use so much 30KV102K, the customer directly purchased a small batch of 30KV602K, and found that After using the capacitor, the capacitor is broken! Where is the problem? The guests carefully analyzed the indicators of 30KV602K, and could not find the problem, the withstand voltage value is 60KV, the high frequency characteristic is above 550KHZ, the loss tangent value is 0.2%, and the temperature characteristic OK, the environment has not changed. However, there seems to be no problem on the surface, but the capacitor actually blows up.
Where is the problem? The customer asked us to analyze it together. Obviously, the results analyzed by us are the same. The two capacitor parameters are normal, the performance is stable, and there is no quality problem. Why can we use six 30KV102K in parallel? It is not possible to use a 30KV602K alone. The reason is in the current.
Yes, on the surface everything should be normal, no problem will occur, but in fact, the current of a few milliamps is allocated to the six capacitors. Now, a capacitor must withstand a few milliamperes. The current, in this high-frequency pulse circuit, it is obvious that this capacitor is difficult to take on the responsibility independently, and it is blown up under overwhelming.
Understand this truth, some other customers' unclear problems have been solved: replace a few small-capacity capacitors with a large-capacity capacitor, pay attention to the change of current! Although it only changes the capacitance Quantity, in fact, we also changed the circuit of the circuit, the parameters change!