How to choose audio capacitor?

• Nominal Parameter:

Nominal parameters are the values listed on the capacitor housing.

 

• Capacitance:

Electrostatic capacity, expressed in terms of UF, it is one of the most important factors when you choose one type capacitor.

• Working voltage:

Working voltage (WV) shall be the nominal safe value, that is, in the application circuit, the nominal voltage shall not be exceeded

• Temperature:

Temperature commonly is 85°and 105°. Under high temperature conditions (such as pure class A amplifier) 105° is better. In general, the optimization of high temperature coefficient is also helpful to improve the performance of other parameters.

• Dissipation Factor(DF):

Sometimes the DF is also represented by tan. DF value is high or low, and temperature, capacity, voltage, frequency are related.DF values are generally not marked on capacitors or showed in the specifications sheet.In the DIY selection of capacitors, you can give priority to the selection of higher withstand voltage, for example the working voltage is 45V, then 50V is not very reasonable. Although there is nothing wrong with using 50V for normal operation under voltage, there is something wrong with DF value. A 63V or 71V withstand voltage will give a better performance. Of course, the higher the voltage is the cost effectiveness will lower.

• Equivalent Series Resistance:

High or low ESR is related to capacitor’s capacity, voltage, frequency and temperature. The lower the ESR requirement, the better. When the rated voltage is fixed, the larger the capacity, the lower the ESR. When the capacity is fixed, ESR can be reduced by choosing a variety with high rated voltage. At low frequency, ESR is high, while at high frequency, ESR is low. High temperature will also make ESR rise. Many brands of equivalent series resistance ESR can be found in the specification.

• Leakage Current:

The aluminum electrolytic capacitor always has leakage, which is determined by its physical structure. Needless to say, the smaller the leakage current, the better! The higher the capacitor capacity is, the greater the leakage current will be. Reducing the working voltage can reduce the leakage current. Conversely, the selection of higher voltage varieties will also help to reduce leakage current. Combined with the above two parameters, it is a simple and feasible method to select high pressure resistant varieties under the same conditions. Reduce the internal resistance, the leakage current, ESR, increase the life. All of these are advantages, but the price will be higher.