Capacitor series circuit characteristics Capacitor parallel connection and series connection differe

The working principle of series capacitance and balancing resistors in half-bridge circuits.

The role of a series capacitor is:

1. The terminal voltage of the line is increased. The purpose of using the inductive reactance of the capacitive compensation line to let the voltage of the line drop, so as to increase the voltage of the receiving end of the line, generally speaking, the voltage at the end of the line can be increased by 20.

2. Improve the transmission capacity of the line. The capacitor itself has compensating reactance, and the voltage drop and power loss of the line are reduced, which in turn increases the transmission capacity of the line.

3. Improve the stability of the system. The increased transmission capacity itself improves static stability. When the line increases the capacitive reactance and reduces the total equivalent reactance of the system, the ultimate power of the transmission is improved, and the dynamic stability of the system is also improved.

4. Improve the power flow distribution of the system. In a closed network, the capacitors are connected in series, and the line reactance is changed, and the current will flow according to the specified line, which meets the requirements of economic power distribution.

5. Reduce the voltage fluctuation at the load end. When the line load is terminated with a highly variable impact load, the capacitor can absorb the sharp fluctuations in voltage.

Answer: Series capacitor is also a kind of reactive power compensation equipment, usually connected in series in series in the ultra-high voltage line of 330kV and above, its main role is to improve the system voltage from the perspective of compensation (reduction) reactance, so as to reduce power loss and improve the stability of the system.

1. The composition is not the same as that of the eggplant shed1) Capacitor series connection refers to the connection of multiple capacitors, series is that each component in the circuit is connected by wires one by one, the total capacitance capacity = the reciprocal of the sum of the reciprocal capacitors of each series capacitance c = 1 (1 c1 + 1 c2 + --1 cn).

2) Capacitor parallel connection refers to the parallel connection of multiple capacitors in parallel, and the parallel capacitor is mainly used to compensate the power system.

Reactive power of inductive loads.

to improve the power factor.

Improve voltage quality and reduce line losses.

2. The current path is different1) There is only one path of series capacitance from the positive electrode, which is directed from the positive electrode to the negative electrode.

2) In a parallel capacitor circuit, there are multiple paths through which the current flows from the positive to the negative.

3. The working state is different after disconnection1) Series capacitor circuit, as long as one of them is disconnected, the whole circuit will be in a non-working state.

2) In parallel capacitor circuits, even if one of the branches is disconnected, the whole circuit will still be in working condition.

Series capacitance and parallel capacitance are two commonly used capacitor connection methods in circuits, and their difference lies in the connection method and the calculation method of total capacitance value.

Series capacitance refers to the connection of multiple capacitors together to form a capacitor series circuit. In a series circuit, the positive and negative tremor terminals of the capacitor are connected sequentially, and the total capacitance value is equal to the reciprocal of the sum of the capacitance values of all capacitors. That is, if there are n capacitors, their capacitance values are 、.. C1, C2, and so on

CN, the total capacitance value is 1 (1 C1 + 1 C2 + 1 CN), and the voltages are distributed across each capacitor individually.

Parallel capacitor refers to the simultaneous connection of multiple capacitors together to form a capacitor parallel circuit. In a parallel circuit, the positive and negative poles of the capacitor are connected separately, and the total capacitance value is equal to the sum of the capacitance values of all capacitors. That is, if there are n capacitors, their capacitance values are 、.. C1, C2, and so on

cn, the total capacitance value is C1 + C2 + CN, and the voltage is equally distributed across each capacitor.

In summary, the difference between series capacitance and shunt capacitance is the connection method and the calculation method of the total capacitance value. A series capacitor is the reciprocal of a plurality of capacitors connected together, and the total capacitance value is equal to the sum of the reciprocal capacitance values of all capacitors; A shunt capacitor is a capacitor that connects multiple capacitors together at the same time, and the total capacitance value is equal to the sum of the capacitance values of all capacitors.

The difference between the two:

The equivalent capacitance of a shunt capacitor bank is equal to the sum of the capacitors in the capacitor bank, while the reciprocal of the equivalent capacitance of a series capacitor bank is equal to the sum of the reciprocal capacitance of the capacitors in the capacitor bank.

The equivalent capacitance of a series capacitor bank is smaller than that of any one of the capacitors in the capacitor bank, whereas the equivalent capacitance of a series capacitor bank is smaller than that of any one of the capacitors in the capacitor bank.

Capacitors are connected in series, the capacitance decreases (the calculation of the total capacitance after series connection, refer to the parallel connection method of resistors), and the withstand voltage increases.

Capacitors are connected in parallel, the capacitance is increased (each capacitance is added), and the withstand voltage is the smallest. Series capacitance: the more the number of series, the smaller the capacitance, but the withstand voltage increases, and its capacity relationship:

1 C 1 C1 1 C2 1 C3 Shunt capacitor: the more the number of parallels, the larger the capacitance, but the withstand voltage remains unchanged, and its capacity relationship: C C1 C2 C3.

The difference between series capacitors and parallel capacitors is mainly in the way they are connected and the capacities.

Series capacitance refers to the series of capacitors that are connected together with the circuit symbol Parallel C. The main function of series capacitors is to increase the total capacity of the capacitors, because the capacity of series capacitors is the reciprocal and one-tenth of the capacity of each capacitor, and the withstand voltage is the sum of the capacitance of each capacitor.

A shunt capacitor is a capacitor that is connected in parallel with a circuit symbol of C. The main function of the shunt capacitor is to increase the total power of the circuit, because the capacity of the shunt capacitor is the sum of the capacitance of each capacitor, and the withstand voltage is the reciprocal sum of the capacity of each capacitor.

In general, series capacitors and shunt capacitors have their own characteristics, and they need to be selected according to the specific situation when used in the circuit.

Capacitor series calculation method: Equivalent branch response capacitance 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 function of capacitors in series or parallel in the circuit is to prevent voltage abrupt changes, absorb the overvoltage in the spike state, and the series resistance plays a damping role, and the resistance consumes the energy of the overvoltage, thereby suppressing the oscillation of the circuit. The resistors connected in parallel absorb the electrical energy of the capacitors to prevent the discharge current of the capacitors from being too large and avoid damage to the devices connected in parallel (such as thyristors).

The simplest capacitors consist of plates at both ends and an insulating dielectric (including air) in the middle. When energized, the plates become electrified, forming a voltage (potential difference), but the entire capacitor is not conductive due to the insulating material in the middle. However, this is the case if the critical voltage (breakdown voltage) of the capacitor is not exceeded.

Any substance is relatively insulating, when the voltage at both ends of the substance increases to a certain extent, the substance can conduct electricity, we call this voltage the breakdown voltage. Capacitors are no exception, and when they are broken down, they are not insulators.

However, in middle school, such voltages are not seen in circuits, so they all work below the breakdown voltage and can be regarded as insulators.

However, in AC circuits, because the direction of the current is a certain function of time. The process of charging and discharging capacitors has time, and at this time, a changing electric field is formed between the plates, and this electric field is also a function of time. In fact, an electric current is passed between the capacitors in the form of an electric field.

1.If it is a DC voltage source, the characteristics of capacitor series voltage division can be introduced according to the middle school physics

1) The total voltage at both ends of the capacitor series circuit is equal to the sum of the voltage division at both ends of each capacitor. i.e. u=u1+u2+u3+....＋un。

2) When the capacitors are connected in series, the voltage distributed on each capacitor is inversely proportional to its capacitance. i.e. un=q cn (Because in a capacitor series circuit, the amount of charge on each capacitor is equal, the higher the capacitance, the lower the voltage distributed by the capacitor, and the lower the capacitance, the higher the voltage distributed. ）

Then the voltage source of 4V, and the voltages on the two capacitors of 1F are 8 3V and 4 3V respectively

2.If it is an AC voltage source, the impedance of the capacitor is xc = 1 j cxc|Inversely proportional to c, will |xc|The same result can be obtained when the voltage division is calculated as a resistor.

Extended information: Series connection is one of the basic ways to connect circuit components. Circuit components (such as resistors, capacitors, inductors, electrical appliances, etc.) are connected or stoveed one by one.

The circuit composed of connecting various electrical appliances in series is called a series circuit. In a series circuit, the current through each consumer is equal.

Main features: Two or more components are arranged in a string, and the first end of each component and the tail end of the previous component are connected into a node, and this node is no longer connected with other nodes. The diagram shows three components in series.

the first end of the element 3 and the end end of the element 2 are connected to form a node q; The root end of element 2 and the tail end of element 1 are connected to form node p. The first end A of Element 1 and the last end B of Component 3 are connected to the other nodes of the circuit, respectively.

The main characteristics of series circuits are:

The current in all series elements is the same current, i total = l1 = l2 = l3 = ......ln。

The total voltage of the components in series is the sum of the terminal voltages of all the components, u total = u1 + u2 + u3 + ......un。

In the circuit illustrated, u is the total voltage, and u1, u2, and u3 are the voltages of the components, u=u1+u2+u3.

The method of judging whether the appliances in a circuit are connected in series or in parallel:

Series and parallel connection are the two most basic forms of circuit connection, and there are certain differences between them. To determine whether the components in a circuit are connected in series or parallel, it is necessary to grasp their basic characteristics, and the specific methods are:

1) Electrical connection method: analyze the connection method of electrical appliances in the circuit, and connect them in series one by one; Parallel between two points in a circuit is parallel.

2) Current flow direction method: when the current flows out of the positive terminal of the power supply, it flows through each component in series in turn; When two branches flow separately in a shirt and finally merge together, it indicates that the circuit is connected in parallel.

3) Removal of component method: arbitrarily remove an electrical appliance to see whether other electrical appliances are working normally, if all electrical appliances have been removed, and other electrical appliances can continue to work, then the connection relationship of these electrical appliances is parallel; Otherwise, it is tandem.

Characteristics of series: the current flowing through each inductor is the same;

l total = l1 + l2 + l3

The voltage of each inductor is equal to the product of the respective inductance value and the current;

The total voltage is equal to the sum of the voltages of the individual inductors.

Characteristics of parallel connection: the voltage at both ends of each inductor is the same;

1/l=1/l1+1/l2+1/l3

The current of each inductor is equal to the quotient of the respective inductor voltage and the self-inductance value;

The total current is equal to the sum of the currents of the individual inductors.

When capacitors are connected in series, the charge on adjacent plates is generated by induction, so the amount of charge carried by each capacitor is equal. In series, there is u total = u1 + u2 + ......un, and because Q=Cu, Q1=Q2=......qn, so q total c total = q1 c1 + q2 c2 + ......qn cn, both sides at the same time to remove q, get 1 c total = 1 c1 + 1 c2 + ......1/cn。

When connected in parallel, the voltage at both ends of each capacitor is equal, and according to the conservation of charge in the circuit, Q total = Q1 + Q2 + ...... can be obtainedqn, and because q=cu in the split, c total u=c1u+c2u+......Liangyuan silver CNU, both sides at the same time about U, you get C total = C1 + C2 + ......cn。Feast.

The series-parallel connection of a capacitor is similar to that of a resistor, but the situation is the same when the resistors are connected in series as in the case of a capacitor in parallel, and the situation is the same as that in which the resistor is connected in series.