High frequency SMD capacitor and low frequency SMD capacitor

    High-frequency SMD capacitor belong to high-frequency low-dielectric capacitor ceramics, mainly alumina ceramics, and their main polarization modes are electron displacement polarization and ion displacement polarization. There are rutile porcelain, calcium titanate porcelain, strontium titanate porcelain, niobium bismuth magnesium porcelain, niobium bismuth zinc porcelain, etc. belonging to high-frequency and high-dielectric capacitor porcelains. The main polarization modes include electron displacement polarization, ion displacement polarization and because of The electron shell inside the ion undergoes polarization caused by strong deformation under the action of an electric field. SMD ceramic capacitor made of these capacitor ceramics are called SMD high-frequency capacitor .

    As high-frequency SMD ceramic capacitor , some are used for impedance matching and other occasions, some are used for temperature compensation at high frequencies, some are used for high-frequency filtering, and some pay special attention to low loss at high frequencies. Called high-frequency high-Q capacitor ), these capacitor  have a common feature, that is, small capacitance, small equivalent series resistance, small equivalent series inductance, small capacitance error, and small size. Obviously, to meet these requirements at the same time, it is not enough to only pay attention to the above-mentioned properties related to the properties of dielectric materials, but also to pay attention to the design and manufacture of capacitor .

Low-frequency SMD capacitor belong to low-frequency strong dielectric capacitor ceramics, which are mainly barium titanate series ceramics. The main polarization mode is the orientation effect of the external electric field on the electrical domains generated by its spontaneous polarization.

In addition to the distinction between high-frequency SMD capacitor and low-frequency SMD capacitor , a new category has recently emerged, that is, SMD capacitor for power supplies. This type of capacitor is used in rectifier circuits from AC to DC, and conversion circuits from DC to DC. It does not require high capacitance accuracy, but it must be large capacitance, low loss, allow large current to pass, low equivalent series resistance, low equivalent series inductance, fast response speed, and good high-frequency characteristics.

    The main types of capacitor are aluminum electrolytic capacitor , SMD ceramic capacitor , in addition to tantalum

Electrolytic capacitor , organic semiconductor (OS: Organic Semiconductor) capacitor , etc.

Sometimes when one capacitor cannot take into account both large capacitance and high speed and high frequency at the same time, two capacitor can be connected in parallel, so that one of them meets the requirements of low frequency and large capacitance, and the other meets the requirements of high speed, high frequency and small capacitance. Requirements.