How to choose a good industrial capacitor？
1 industrial capacity, the bigger the better.
Many people in the industrial capacity of the replacement of a large capacity is often used in industrial capacity. We know that although the larger the industrial capacity, the greater the ability to compensate for the current supplied by the IC. And not to say that the volume of industrial capacity increases, the increase in costs, but also affect the air flow and heat dissipation. The key point is that there is parasitic inductance in the industrial capacitance, and the industrial capacitor discharge circuit will resonate at a certain frequency point. At the resonance point, the industrial capacitance of the impedance is small. Therefore, the discharge circuit of the minimum impedance, the effect of complementary energy is also the best. But when the frequency exceeds the resonance point, the impedance of the discharge circuit begins to increase. The bigger the capacitance value is, the lower the resonance frequency is, the frequency range of the effective compensation current is smaller. From the point of view that the ability to provide high frequency current, the bigger the industrial capacitor is, the better the idea is wrong, there is a reference value of the general circuit design.
2 the same capacity of industrial capacitors, shunt, the more the smaller industrial capacitors, the better
Pressure value, temperature resistance, capacitance value, ESR (equivalent resistance) and so on are several important parameters of industrial capacitance, for ESR nature is the lower the better. ESR and industrial capacity, frequency, voltage, temperature and so on are related. When the voltage is fixed, the capacity is bigger, the ESR is lower. In the design of the board with a number of small industrial capacitors and even more out of space and PCB restrictions, so that some people think, the more parallel small resistance, ESR, the lower the better. Theory is so, but to take into account the impedance of the industrial capacity of the solder joints, the use of a number of small industrial capacitors in parallel, the effect is not necessarily prominent.
The lower the 3.ESR, the better the effect.
With the increase of our power supply circuit above, for the input of industrial capacity, the capacity to enter the industrial capacity of a large point. Relative capacity requirements, the requirements of the ESR can be appropriately reduced. Because the input industrial capacity is mainly pressure, followed by the absorption of MOSFET switching pulse. For the output of industrial capacitors, the requirements and capacity of the pressure can be reduced to a point. ESR requirements are a little bit higher, because there is a guarantee of sufficient current through the amount of. But it should be noted here is that the ESR is not the lower the better, low ESR industrial capacitance will cause the oscillation of the switching circuit. And the vibration circuit is complicated and the cost will be increased. Board design, there is generally a reference value, this as a component selection parameters, to avoid vibration circuit and lead to increased costs.
4 good industrial capacity represents the high quality.
"The only industrial capacitance theory" has been very popular, some manufacturers and media also deliberately put this thing into a selling point. In the design of the board, the level of circuit design is the key. And some manufacturers can use two-phase power supply to make more stable than some manufacturers use four phase power, the use of a high priced industrial capacity, not necessarily make good products. The measure of a product, to a full range of multi angle to consider, must not exaggerate the role of the capacitor industry naturally or half unconsciously.
