Capacitor capacitance and tolerance

1.Capacitor capacitance

(1) "Capacitor", which is an abbreviation of a capacitor, is a "charged container" and is a device that holds a charge. Any two conductors (including wires) that are insulated from each other and are closely spaced together form a capacitor. It is widely used in blocking, coupling, bypassing, filtering, tuning loop, energy conversion, control circuit, etc. It is one of the electronic components widely used in electronic equipment, and is represented by the letter C;

(2) The other "capacitance" is capacitance, which refers to the amount of charge stored at a given potential difference, denoted as C, and the international unit is Farad (F). Generally, the electric charge moves in the electric field. When there is a medium between the conductors, the electric charge is hindered and the electric charge accumulates on the conductor, causing the accumulated storage of the electric charge. The stored electric charge amount is called a capacitance. In circuit science, under a certain potential difference (1U), the capacitor's ability to store charge, called capacitance, is denoted as C, and the unit is Farah. The formula is C=Q/U, Q is the charge, and U is the voltage.

2. Capacitance tolerance

Depending on the application, the tolerance of the film capacitor can be divided into general purpose and precision capacitor applications. The general purpose film capacitors do not require high capacitance accuracy of the capacitors, and the corresponding tolerances can be larger, and 5%, 10%, or 20% of the soil are all acceptable. For applications such as bypassing, coupling or less demanding timing and general delays, a 10% tolerance film capacitor can be selected; for slightly higher applications, a 5% tolerance film capacitor can be selected; For applications such as bypass, coupling, and high-frequency rectification filtering that do not require tolerance at all, a 20% tolerance film capacitor can be selected.

For precision capacitors such as oscillating circuits and resonant circuits, these circuits with high tolerance requirements usually have a tolerance of 2% or even 1%. The dielectric material of this high-precision film capacitor is small or basic with temperature. Without change, such a circuit is compensated by a variable inductance adjustment in addition to the capacitance value.