How to calculate the relationship between the capacitance of a capacitor and the voltage?

Capacitors in parallel:

It is equivalent to an increase in the area of the electrode, and an increase in the capacitance. The total capacity when connected in parallel is the sum of the capacitances: c1 c2 c3 ......

Series connection of capacitors:

1 C string 1 C1 1 C2 1 C3 (the total capacitance decreases after series connection) The process is obtained: if the applied voltage of the three capacitors in series is U, then U1 U2 U3 Q1 C1 Q2 C2 Q3 C3, and the charge Q1 Q2 Q3 Q3 Q, so Q C string (1 C1 1 C2 1 C3)q

When the containers are connected in series, the resistance value of the parallel resistance is smaller than the insulation resistance of the capacitor, so that the voltage on each capacitor is evenly distributed, so as to avoid damage to the capacitor due to uneven voltage distribution. It can also be seen that the series and parallel calculations of capacitors are exactly the opposite of the series and parallel calculations of resistors. Voltage is the voltage when charging, capacity and current, the relationship between voltage and power is similar, and load, voltage and capacity are quantitative, the smaller the load resistance, the larger the current, the shorter the time When the voltage and load are quantitative, the larger the capacity, the current is unchanged, the longer the time But in the actual discharge circuit, the general load is unchanged, the voltage of the capacitor is gradually decreasing, and the current is gradually decreasing.

The formula for the relationship between capacitance and voltage is: capacitance =The amount of chargevoltage, i.e. c=q u. The relationship between capacitance and voltage is inversely proportional, usually referred to as the ability of the capacitor to accommodate the charge is capacitance, capacitance is an inherent property of the capacitor, determined by the capacitor plate material, the distance between the two plates, and has no relationship with voltage.

For mezzanine plate capacitors, there is a general formula c=q u.

It is generally believed that an isolated conductor and infinity constitute a capacitance, and the grounding of the conductor is equivalent to being connected to infinity and connected to the earth as a whole. The ratio of the charge q carried by the capacitor to the voltage u between the two poles of the capacitor is called the capacitance of the capacitor. In electrical circuits, a potential difference is given.

A capacitor's ability to store an electric charge, called capacitance, is labeled C. The International System of Units is used.

The unit of capacitance is farad.

farad), marked as f.

Factors that determine the size of the capacitance:

The magnitude of the capacitance is not determined by q (charged) or u (voltage), i.e. the determination of the capacitance is: c = s 4 kd. Among them, are the Greek letters.

Pronounced as epsilon, is a constant, s is the area opposite the capacitive plate, d is the distance of the capacitive plate, and k is the electrostatic force constant. A common parallel plate capacitor with a capacitance of c = s d ( is the dielectric constant of the medium between the plates.

s is the area of the plates, and d is the distance between the plates).

Clear: The dielectric constant of the insulating material between the plates used in the general capacitor is a fixed value, so the capacitance of the capacitor has nothing to do with the voltage applied at both ends of the plate.

However, in the case of piezoelectric ceramic materials, capacitors made of dielectric materials are used as dielectric materials because their dielectric constant is related to the voltage applied to them.

For example, in FM broadcasting, this capacitor is often used to change the change of signal from voltage to frequency (frequency modulation).

In a varistor diode made of semiconductor material, when the applied voltage changes, the junction capacitance between the two poles is equivalent to the structural change between the capacitor plates due to the migration of electrons in the material with the change of voltage.

From a quantum mechanical point of view, a capacitor stores electric field energy, which is the energy of the interaction of stationary charges, and the larger the capacity of the capacitor, the more charge it stores, and the more charge it has, the higher the voltage required. Relationship between voltage, charge, and capacitance: u=w q and c=q u.

The total capacitance of the capacitance = the reciprocal of the sum of the reciprocal capacitors of each series series c = 1 (1 c1 + 1 c2 + --1 cn), series connection means that the various components in the circuit are connected by wires one by one.

Capacitance series calculation method: The equivalent capacitance formula is similar to resistor parallel: c (c1*c2) (c1+c2). For example, when two 100 microfarey capacitors are connected in series, they become one 50 microfarature capacitor.

The withstand voltage of the two capacitors in series is the sum of the two, and the capacitance is the reciprocal sum of the two. The parallel withstand voltage of the two capacitors is the lowest withstand voltage of the two, and the capacitance is the sum of the two. To put it simply, the series withstand voltage increases and the capacity decreases. The parallel withstand voltage remains unchanged and the capacity increases.

The formula of voltage is u=i r, the formula of the electric quantity is q=i t, and the relationship between voltage and electricity is: q=u r t.

Voltage. 1) Introduction to voltage: also known as potential difference or potential difference, it is a physical quantity that measures the energy difference between a unit charge in an electrostatic field due to different electric potentials.

Its magnitude is equal to the work done by a unit positive charge to move from point A to point B due to the action of an electric field force, and the direction of the voltage is specified as the direction from the high potential to the low potential.

2) SI units of voltage: volts, commonly used units are millivolts, microvolts, kilovolts, etc.

3) Voltage law: Voltage is what drives the directional movement of the charge to form an electric current. The reason why the current is able to flow in the wire is also because of the difference between high and low potential in the current.

This difference is called the potential difference, also known as the voltage. In other words. In a circuit, the potential difference between any two points is called the voltage of these two liters.

4) Classification: Voltage can be divided into high voltage, low voltage and safety voltage.

Electricity. 1) Introduction to electricity: The amount of electricity indicates the amount of charge carried by an object. Generally speaking, the quantity of electric charge is called the amount of electricity, which is represented by the symbol Q, and the unit is the library, and the coulomb is a large unit.

Capacitance. The production of the spine is a fixed value, and it has nothing to do with voltage. But the amount of stored charge.

With the voltage there is a sparrow off. qc

The higher the voltage, the more charge is stored.

100uf/25v

And. 100uf/50v

The capacitance is the same, but the maximum amount of stored power is different depending on the voltage it is subjected to.

The capacitance power change dq circuit will flow through the electric power dq, with time dt, current i = dq dt according to the capacitance formula q = cu, dq = cdu to get i = dq dt = cdu dt

Linear capacitive element slip voltage current relationship:

Let the voltage and current be a function of time, and now find the relationship between voltage and current. When the voltage between the plates changes, the charge on the plates also changes, and a current is generated in the capacitive element. This current can be obtained by i=dq dt =c(du dt).

The above equation shows that the magnitude and direction of the current depend on the rate of change of voltage versus time.

Capacitance from the physical point of view, it is a static charge storage medium, may be permanent charge, this is its characteristic, it is widely used, it is an indispensable electronic component in the field of electronics and electricity.

It is mainly used for power supply filtering.

Signal filtering, signal coupling, resonance.

Filtering, compensation, charge and discharge, energy storage, DC isolation and other circuits.

Formula for capacitance (defined):

For a capacitor, if the potential difference between the two stages is 1 volt with 1 bank, the capacitance of this capacitor is 1 farad, i.e., c=q u.

However, the magnitude of the capacitance is not determined by q (charged) or you (voltage), i.e. the capacitance is determined by the following formula: c = rs 4 kd. where r is the relative permittivity, s is the area opposite the capacitive plate, d is the distance of the capacitive plate, and k is the electrostatic constant.

Common parallel plate capacitors, the capacitance is c = s d ( is the dielectric constant of the medium between the plates, r 0, 0 = 1 4 k, s is the plate area, d is the distance between the plates).

1) The formula for calculating the potential energy of a capacitor is: e=c*(u 2) 2=qu 2=(q 2) 2c.

2) The formula for calculating the parallel connection of multiple capacitors: c=c1+c2+c3+....＋cn。

3) The formula for calculating the series connection of multiple capacitors: 1 c = 1 c1 + 1 c2 + ....＋1/cn。

4) Three capacitors in series: c=(c1*c2*c3) (c1*c2+c2*c3+c1*c3).

The above content reference: Encyclopedia - Capacitors.