12:04 AM

Solar Inverter for Home

Solar Inverter for Home:

Introduction to Solar Inverter:

We see many people using Solar inverters these days which proves that its necessity has been increased in the current years. A Solar inverter is similar to a normal electric inverter but uses the energy of the Sun i.e. Solar energy. A solar inverter helps in converting the direct current into alternate current with the help of solar power. Direct power is that power which runs in one direction inside the circuit and helps in supplying current when there is no electricity. Direct currents are used for small appliance like mobile e phones, MP3 players, IPod etc. where there is power stored in the form of battery. In case of alternative current it is the power that runs back and forth inside the circuit. The alternate power is generally used for house hold appliances. A solar inverter helps devices that run on DC power to run in AC power so that the user makes use of the AC power. If you are thinking why to use solar inverter instead of the normal electric one then it is because the solar one makes use of the solar energy which is available in abundant from the Sun and is clean and pollution free.

Solar inverters are also called as photovoltaic solar inverters. These devices can help you save lot of money. The small-scale grid one have just two components i.e. the panels and inverter while the off grid systems are complicated and consists of batteries which allows users to use appliances during the night when there is no Sunlight available. The solar panel and the batteries that are placed on rooftops attract Sun rays and then convert the Sunlight into electricity. The batteries too grab the extra electricity so that it can then be used to run appliances at night.

Working of Solar Inverter:

Now after knowing what a solar inverter is, let’s talk about its working. Solar panels produce direct electricity with the help of electrons that are moving from negative to positive direction. Most of the appliances that we use at home work on alternative current. This AC is created by the constant back and forth of the electrons from negative to positive. In AC electricity the voltage can be adjusted according to the use of the appliance. As solar panels only produce Direct current the solar inverter is used to convert the DC to AC.

An inverter produces square waves or a sine wave which can be used for running lights, televisions, lights, motors etc. However these inverters also produce harmonic distortion. Expensive inverters make use of lots of steps to produce a sine wave and thus are found in residential solar inverters. Basically inverters should be a large one so that it supplies enough power to all the necessary appliances.

An inverter s easy to buy but choosing the right solar inverter for your appliance is more important. Thus you must always consult a solar professional before buying on. We know that the energy derived from sun is solar energy which is one of the cleanest sources of energy. Also it can be used to provide lighting to houses.

You can make us of the photovoltaic tiles that attract energy from Sun and converts it into a clean form of electricity which can be used to light, houses, industries and companies. The cells of photovoltaic consist of positive and negative silicon that is placed underneath a slice of glass. When the protons of the Sunlight hit the PV cells they knock the neutrons present in the silicon. Now the negative charged neutrons get attracted to the silicon but then are held inside a magnetic field. The wires attached on the silicon catch hold of these neutrons and while connecting to the circuit, current is formed. This then gives space for direct electricity and for converting that into alternate electricity an inverter is used so that the house appliances can run. As mentioned before major of the house appliances work on alternate current hence an inverter is used to convert DC to AC.

Solar power apart from making your home appliances work can also be used to heat water and swimming pools too.

How to Make a Solar Inverter?

The energy derived from Sun is a renewable one and is totally free of cost. We have learnt how the solar inverter helps in providing electricity and now we shall learn how a solar inverter is made. A solar panel is capable enough to convert the heat or energy of the Sun into direct current.

Solar Inverter Design:

To easily understand the construction of a solar inverter lets discuss the following construction sample:-

According to the circuit diagram initially do the assembling of the oscillator part which consist of the small components & IC. It is finely completed by interrelating the part leads itself and fusing the joints.
Now place the power transistors into the acutely pierced aluminum heat sinks. This is crafted by cutting aluminum sheet into specified sizes and bending their sides, so that it can be hold tightly.
Make use of mica isolation kit to fix transistors in the aluminum heat sink, evade short circuiting & direct contact of the transistors from ground & each other.
Fasten the heat sink congregation to the bottom of a properly ventilated, strong, thick gauge metal enclosed space.
Also fasten the power transformer next to the aluminum heat sinks by making use of screw & bolts.
Now join the suitable points of the assembled circuit board & power transistors on the aluminum heat sinks.
At last connect the power transistor’s productions to the subsequent winding of the power transformer.
End the assembly by fastening and interlocking the outer electrical fittings such as switches, mains cord, fuses, sockets, and the battery inputs.
A voluntary solar power supply circuit and a transformer may be added within to charge the battery when necessary (check diagram).

Solar Inverter Circuit Diagram:

To understand well how to construct a solar inverter, it is vital to study how the circuit operates through with the help of following steps:

N1 & N2 gates of IC 4049 are employed as an oscillator. It carries out the key role of providing square waves to the inverter division.
N3 to N6 gates are employed as buffers so that the circuit is not dependent on load.
Continuously changing voltage from the buffer phase is useful to the bottom of the current amplifier transistors T1 & T2. These transistors perform in harmony with the practical changing voltage and boost it to the bottom of the output transistors T3 & T4.
These producing power transistors swing at a full oscillation, providing the total battery voltage.
This energy produced is from solar panel & is employed to power the output load.

Solar Inverter Advantages:

After knowing in detail what a solar inverter is and how different useful it is to make appliances work at residential and industrial levels we must discuss about the many advantages of the device.

Solar energy has always helped in reducing global warming and green house effect.
Also use of solar energy helps in saving money many people have started using solar based devices
A solar inverter helps in converting the Direct current into batteries or alternative current. This helps people who use limited amount of electricity.
There is this synchronous solar inverter that helps small homeowners and power companies as they are large in size
Then there is this multifunction solar inverter which is the best among all and works efficiently. It converts the DC power to AC very carefully which is perfect for commercial establishments
This inverter is cost effective i.e. less expensive than generators
Apart from solar inverters there are other devices too that make use of solar energy namely, solar cooker, heater.
Solar inverters are the best way and they are better than the normal electric ones. Also their maintenance does not cost much money

Solar Inverter Disadvantages:

Initially you need to shell out a lot of money for buying a solar inverter
It will work effectively and produce direct current only when the Sunlight is strong.
The solar panels that are used to attract Sunlight requires lots of space
The device can work efficiently only if the presence of the Sun is strong.
Solar Inverters can work when there is no Sunlight but provided their battery is charged fully with the help of Sunlight.

After counting on some of the disadvantages of solar inverter we can state that when a device is very useful at some point of time it too requires proper maintenance and when it comes to a solar device the equipment of solar energy is must. So buy a solar device only if you have plenty of solar energy available.

REFERENCE // Electronics Hub

7:57 PM

Capacitance in AC Circuits

Capacitance in AC Circuits:

Introduction:

When DC supply voltage is applied to the capacitor,the capacitor is charged slowly and finally it reaches to fully charged position. At this point the charging voltage of a capacitor is equal to the supply voltage. Here the capacitor acts as an energy source as long as voltage is applied. Capacitors don’t allow current (i) through them after they fully charged.The current flowing through the circuit depends on the amount of charge in the plates of capacitors and also the current is directly proportional to the rate of change of voltage applied to the circuit. i.e. i = dQ/dt = C dV(t)/dt.

If AC supply voltage is applied to the capacitor circuit then the capacitor charges and discharges continuously depending on the rate of frequency of supply voltage. The capacitance of a capacitor in AC circuits depends on the frequency of supply voltage applied to it. In AC circuits the capacitors allow current when the supply voltage is continuously changing with respect to time.

AC Capacitor Circuit:

In the above circuit we observed that a capacitor is directly connected to the AC supply voltage. Here the capacitor continuously charges and discharges depending on the changes in supply voltage, because the AC supply voltage value is constantly increases and decreases. We all know that the current flowing through the circuit is directly proportional to the rate of change of voltage applied.

Here the charging current has its high value, if the supply voltage crosses its value from positive half cycle to the negative half cycle and vice versa. i.e. at 00 and 1800 in sine wave signal. The current through the capacitor has its minimum value when the supply voltage in sine wave crosses over at its maximum or minimum peak value (Vm). Hence we can say that the charging current flowing through the circuit is maximum or minimum depending on the supply voltage levels in sine wave.

AC Capacitor Phasor Diagram:

Figure 2. Phasor diagram of AC capacitor.

The phasor diagram of AC capacitor is shown in the above figure, here the voltage and currents are represented in sine wave forms. In the above figure we observed that at 00 the charging current is at its maximum value because the voltage is increasing slowly in positive direction. At 900 there is no current flow through the capacitor because at this point the supply voltage is at its maximum peak value.

At 1800 point the voltage slowly decreases to zero and current is at maximum value in the negative direction. Again the charging reaches to its maximum value at 3600, because at this point the supply voltage is at minimum value.

From the waveforms in the above figure we can see that, the current is leading the voltage by 900. Hence we can say that in an ideal capacitor circuit the AC voltage lags the current by 900.

Capacitive Reactance:

We know that the current flowing through the capacitor is directly proportional the rate of change of applied voltage but capacitors also offer some form of resistance against the current flow same as like resistors. This resistance of capacitors in AC circuits is called as capacitive reactance or commonly known as reactance. Capacitive reactance is the property of a capacitor which opposes the flow of current in AC circuits. It is represented with symbol Xc and measured in Ohms same as like resistance.

We need some extra energy over capacitive reactance to charge up a capacitor in the circuit. This value is inversely proportional to the capacitance value and the frequency of supply voltage.

Xc∝ 1/c and Xc∝ 1/f.

The equation for capacitive reactance and parameters which influences them are discussed in below.

Capacitive Reactance,

XC = 1/2πfC = 1/ωC

Here,

XC = Reactance of capacitor

f = frequency in HZ

C = Capacitance of a capacitor in Farads

ω (omega) = 2πf

From the above equation we understood that capacitive reactance is high where the frequency and capacitance values are at low and at this stage the capacitor acts as a perfect resistor. If the frequency of supply voltage is high then the reactance value of capacitor is low and also at this stage capacitor acts as a good conductor. From the above equation it is clear that the reactance is zero if the frequency is infinity and the reactance value is infinity where the frequency is at zero.

Capacitive Reactance against Frequency:

Figure 3.Relation between Reactance and Frequency.

The above figure shows the relation between the capacitive reactance, current and frequency of the supply voltage. Here we observed that if frequency is low then the reactance is high. The charging current increases with increase in frequency, because the rate of change of voltage increases with time.The reactance is at infinite value where the frequency is zero and vice versa.

AC Capacitance - Example No1:

Find the rms value of current flowing through the circuit having 3uF capacitor connected to 660V and 40Hz supply.

Capacitive Reactance,

XC = 1/2πfC

Here,

f = 40HZ

C = 3uF

Vrms = 660V

Now,

XC = 1/(2 × 3.14 × 40HZ × 3 × 10-6) = 1326Ω

Irms = Vrms/XC = 660V/1326Ω = 497mA

AC Capacitance - Example No2:

Find the rms value of current flowing through the circuit having 5uF capacitor connected to 880V and 50Hz supply.

Capacitive Reactance,

XC = 1/2πfC

Here,

f = 50HZ

C = 5uF

Vrms = 880V

Now,

XC = 1/(2 × 3.14 × 50HZ × 5 × 10-6) = 636Ω

Irms = Vrms/XC = 880V/636Ω = 1.38 A

From the above two examples practically we observed that the reactance of a capacitor depends on the frequency of the supply voltage and it is inversely proportional relation. In example 1 , the reactance is 1326Ω for the frequency of 40HZ but the reactance value decreases to 636Ω when the frequency increases to 50HZ which is shown in example 2.Hence it is clear that the reactance of a capacitor is inversely proportional to the frequency and capacitance.

REFERENCE // Electronics Hub

7:48 PM

Capacitive Voltage Divider

Capacitive Voltage Divider:

Introduction:

In a voltage divider circuit,the supply voltage or circuit voltage is distributed among all the components in the circuit equally,depending on the capacity of those components.

The construction of capacitive voltage divider circuit is same as like resistive voltage divider circuit. But like resistors, the capacitive voltage divider circuit is not affected by the changes in the frequency even though it uses reactive elements.

The capacitor is a passive component which stores electrical energy in the metal plates. A capacitor has two plates and these two are separated by non-conducting or insulating material, such as called as “dielectric”.

Here the positive charge is stored on one plate and negative charge is stored on another plate.

When DC current is applied to the capacitor, it charges fully. The dielectric material between the plates acts as insulator and also it opposes the current flow through the capacitor.

This opposition to supply current through the capacitor is called reactance (XC) of a capacitor. The capacitor reactance is also measured in ohms.

A fully charged capacitor acts as an energy source, because a capacitor stores energy and discharges it to the circuit components.

If an AC current is applied to the capacitor then the capacitor continuously charges and discharges the current through its plates.In this time the capacitor also has reactance which varies depends on supply frequency.

We know that the charge which is stored in the capacitor depends on the supply voltage and the capacitance of a capacitor.

In the same way the reactance also depends on some parameters, now we see the parameters which influence the reactance of a capacitor.

If a capacitor has smaller capacitance value , then the time required to charge a capacitor is less , i.e. smaller RC time constant is required. In the same way the RC time constant is high for larger capacitance value of capacitors.

From this we observed that , larger capacitance value capacitor has less reactance value where as smaller capacitance value of capacitor has larger reactance value. i.e. the reactance of a capacitor is inversely proportional to the capacitance value of the capacitor.

XC∝ 1/C

If the frequency of applied current is low then the charging time of capacitor increases,it indicates that reactance value is high. In the same way if the frequency of applied current is at high, then the reactance of the capacitor is low.

From this we can observe that the reactance of a capacitor is inversely proportional to the frequency.

Finally, we can say that, the reactance (XC) of any capacitor is inversely proportional to the frequency (f) and the capacitance value (C).

XC∝ 1/f

Capacitive Reactance Formula:

Already we know that the capacitive reactance is inversely proportional to the frequency and capacitance value of the capacitor. Thus formula for reactance is

XC = 1/2πfC

Here,

XC = Reactance of a capacitor in ohms (Ω)

f = Frequency in Hertz’s (HZ)

C = Capacitance of a capacitor in Farads (F)

π = Numeric constant (22/7 = 3.142)

Voltage Distribution in Series Capacitors:

If the capacitors are connected in series , the voltage distribution between the capacitors is calculated. Because the capacitors have different voltage values depending on the capacitance values in series connection.

The reactance of a capacitor which opposes the flow of current , depends on the value of capacitance and frequency of the applied current.

So now let us see how the reactance affects the capacitors , by calculating the frequency and capacitance values. Below circuit shows the capacitive voltage divider circuit in which 2 capacitors are connected in series.

Capacitive Voltage Divider:

The two capacitors which are connected in series have the capacitance values of 10uF and 22uF respectively. Here the circuit voltage is 10V,this voltage is distributed between both capacitors.

In the series connection all the capacitors have same charge (Q) on it but the supply voltage (VS) is not same for all capacitors.

The circuit voltage is shared by the capacitors depending on the capacitance values of the capacitors.i.e. in the ratio of V = Q/C.

From these values we have to calculate the reactance (XC) of each capacitor by using frequency and capacitance values of capacitors.

Capacitive Voltage Divider - Example No1:

Now we will calculate the voltage distribution to the capacitors 10uF and 22uF which are given in the above figure which have 10V supply voltage with 40HZ frequency.

Reactance of 10uF capacitor,

XC1 = 1/2πfC1 = 1/(2*3.142*40*10*10-6) = 400Ω

Reactance of 22uF capacitor,

XC\2 = 1/2πfC2 = 1/(2*3.142*40*22*10-6) = 180Ω

Total capacitive reactance of a circuit is,

XC= XC1+ XC2= 400Ω + 180Ω = 580Ω

CT= C1C2/(C1+C2) = (10*22*10-12)/(32*10-6) = 6.88uF

XCT = 1/2πfCT = 1/(2*3.142*40*6.88*10-6) = 580Ω

The current in the circuit is,

I = V/XC = 10V/580Ω = 17.2mA

Now, the voltage drop across each capacitor is,

VC1 = I*XC1 = 17.2mA*400Ω = 6.9V

VC2 = I*XC2 =17.2mA*180Ω = 3.1V

Capacitive Voltage Divider - Example No2:

Now we calculate the voltage drops across the capacitors 10uF and 22uF which are connected in series and they operate with 10V supply voltage of 4000HZ (4KHZ) frequency.

Reactance of 10uF capacitor,

XC1 = 1/2πfC1 = 1/(2*3.142*4000*10*10-6) = 4Ω

Reactance of 22uF capacitor,

XC\2 = 1/2πfC2 = 1/(2*3.142*4000*22*10-6) = 1.8Ω

Total capacitive reactance of a circuit is,

XC= XC1+ XC2 = 4Ω+1.8Ω = 5.8Ω

CT = C1C2/(C1+C2) = (10*22*10-12)/(32*10-6) = 6.88uF

XCT = 1/2πfCT = 1/(2*3.142*4000*6.88*10-6) = 5.8Ω

The current in the circuit is,

I = V/XCT = 10V/5.8Ω = 1.72A

Now, the voltage drop across each capacitor is,

VC1 = I*XC1 = 1.72A*4Ω = 6.9V

VC2 = I*XC2 = 1.72A*1.8Ω = 3.1V

From the above two examples we can conclude that the lower value capacitor (10uF) will charge to a higher voltage (6.9V), and the higher value capacitor (22uF) will charge itself to a lower voltage level(3.1V).

Finally the sum of two capacitor voltage drops values are equal to the supply voltage (i.e. 6.9V+3.1V=10V). These voltage values are same for all frequency values, because the voltage drop is independent of frequency.

The voltage drops for the two capacitors is same in both the examples where the frequency is different. The frequency is either 40HZ or 40KHZ the voltage drops across capacitors is same in both cases.

The current flowing through the circuit changes depending on the frequency. Current will increase with increasing the frequency, it is 17.2mA for 40HZ frequency but it is 1.72A for the frequency 4KHZ, i.e. the current will increase almost 100 times by increasing frequency 4HZ to 4KHZ.

Finally we can say that the current flowing through the circuit is directly proportional to the frequency (I α f).

Summary:

The opposition for the flow of current in the capacitor is known as reactance (XC) of a capacitor. This capacitive reactance is influenced by the parameters like capacitance value,frequency of supply voltage and also these values are inversely proportional to the reactance.
The AC voltage divider circuit will distribute the supply voltage to all the capacitors depending on their capacitance value.
These voltage drops for the capacitors are same for any frequency of supply voltage. i.e. the voltage drops across capacitors are independent on frequency.
But the current flowing is depending on frequency and also these two are directly proportional to each other.
But in DC voltage divider circuits, it is not an easy task to calculate the voltage drops across capacitors as it depends on reactance value, because the capacitors block DC current flow through it after fully charged.
The capacitive voltage divider circuits are used in large electronics applications.Mainly used in capacitive sensitive screens those change their output voltage when it is touched by a person finger.
And also used in transformers to increase voltage drop where generally the mains transformer contains low voltage drop chips and components.
Finally one thing to say is in voltage divider circuit the voltage drops across capacitors are same for all frequency values.

REFERENCE // Electronics Hub

7:38 PM

Capacitors in Series and Parallel

Capacitors in Series and Parallel:

Capacitor in Series:

Capacitors in series meanstwo or more capacitors are connected in a single linei.e positive plate of the one capacitor is connected to the negative plate of the next capacitor. All the capacitors in series have equal charge (Q) and equal charging current (iC).

Consider N- numbers of capacitors are connected in series, then

QT =Q1 = Q2 = Q3 = ———- = QN

IC = I1 = I2 = I3 = ——— = IN

Capacitors in a Series Connection:

The following circuits show the series connection of group of capacitors.

series connection of N-number of capacitors.

series connection of two capacitors.

In this circuit the charge (Q) stored in all capacitors is same because every capacitor has the charge which is flowing from the adjacent capacitor. The voltage drop in all capacitors is different from each other. But the total voltage drop applied between input and output lines of the circuit is equal to the sum of all the individual voltage drops of each capacitor. The equivalent capacitance of the circuit is Ceq = Q/V.

Thus,

VT = V1 + V2

Ceq = Q/V1 + Q/V2

1/Ceq = (V1+ V2)/Q

VT = Q/Ceq = Q/C1 + Q/C2

Series Capacitors Equation:

1/Ceq = 1/C1 + 1/C2 +……… + 1/CN

When the capacitors are in series connection the reciprocal of the equivalent capacitance is equal to the sum of the reciprocals of the individual capacitances of the capacitors in the circuit.

From the figure 2, the reciprocal of equivalent capacitance value of the circuit is equal to the sum of reciprocal capacitances values of two capacitors C1 and C2, the expression is given below.

1/Ceq = 1/C1 + 1/C2

Capacitors in Series - Example No1:

We assume that the values of two capacitors in the above figure2 are 0.4uF and 0.5uF respectively. Now we can calculate the equivalent capacitance for the two capacitors in series as,

1/Ceq = 1/C1 + 1/C2

1/Ceq = (C1 + C2)/ C1C2

Ceq = (C1C2) / (C1 + C2)

Ceq = (0.4uF*0.5uF) / (0.4uF+0.5uF)

Ceq = 0.22uF

We know that the equivalent capacitance of the capacitors in series connection is less than the value of the smallest capacitor in the circuit. In that way here also we get the equivalent value 0.22 uF is less than the smallest capacitance 0.4 uF in the series connection of the given two capacitors circuit.

Capacitors in Series - Example No2:

Calculate the equivalent capacitance and the individual voltage drops across the set of two capacitors in series have 0.1uF and 0.2uF respectively when connected to a 12V a.c. supply.

Equivalent capacitance,

1/Ceq = 1/C1 + 1/C2

Ceq = (C1C2) / (C1 + C2)

Ceq = (0.1uF*0.2uF) / (0.1uF+0.2uF)

Ceq = 0.066uF = 66nF

Voltage drops across the two given capacitors in series are,

V1 = (C2*VT)/ (C1+C2) = (0.2uF*12V)/ (0.1uF+0.2uF) = 8Volts

V2 = (C1*VT)/ (C1+C2) = (0.1uF*12V)/ (0.1uF+0.2uF) = 4Volts

From these results we observed that the equivalent capacitance 66nF is less than the smallest capacitance 0.1uF of the given two capacitors. The individual voltage drops across the given two capacitors are different. But the sum of individual voltage drops of both the capacitors is equal to the total voltage. i.e 8V+4V=12V.

Now we calculate the charge stored in individual capacitor,

Q1 = V1* C1 = 8V * 0.1uF = 0.8uC

Q2 = V2* C2 = 4V * 0.2uF = 0.8uC

Here we observed that equal charge 0.8uC is stored in both the capacitors C1 and C2 which are connected in series.

Capacitors in Series Summary:

The equivalent capacitance of the capacitors connected in series chain is, the reciprocal of the equivalent capacitance is equal to the sum of the reciprocals of all the individual capacitances of the capacitors connected in series. All the capacitors which are connected in series have the equal charge (Q). The charging current ( iC) is also same for all the individual capacitors which are connected in series like iC=i1= i2 etc.

The voltage drops for individual capacitors in series connection are different. But the sum of all the individual voltage drops is equal to the total voltage across the circuit. i.e.VT = V1+V2 etc . A large value of capacitance will result in a smaller voltage drop while a small capacitance value will result in a larger voltage drop.

Capacitors in Parallel Circuits:

Capacitors in parallel means two or more capacitors are connected in parallel way, i.e. both of their terminals are connected to each terminal of the other capacitor or capacitors respectively. All the capacitors which are connected in parallel have the same voltage and is equal to the VT applied between the input and output terminals of the circuit. Then, parallel capacitors have a ‘common voltage’ supply across them .i.e. VT = V1 = V2 etc.

The equivalent capacitance, Ceq of the circuit where the capacitors are connected in parallel is equal to the sum of all the individual capacitances of the capacitors added together. This is because the top plateof each capacitor in the circuit is connected to the top plate of adjacent capacitors. In the same way the bottom plate of each capacitor in the circuit is connected to the bottom plate of adjacent capacitors.

The following circuits show parallel connection between groups of capacitors. Figure3 has N-number of capacitors and figure 4 has two capacitors connected in parallel.

Parallel connection of two capacitors,

In above figure the total charge (Q) across the circuit is divided between the two capacitors, means the charge Q distributes itself between the capacitors connected in parallel. Because the voltage drop across individual capacitors is equal and also it is equal to the total voltage applied to the circuit. But the total charge Q is equal to the sum of all the individual capacitor charges connected in parallel. i.e. From the above figure the two different capacitors C1 and C2 have two different charges Q1 and Q2 respectively. Here Q=Q1+Q2

Now we see the equivalent capacitance of the capacitors C1 and C2 connected in parallel which shown in the above figure.

We know the formula,

Q=Ceq VT

Here, Q = Q1+Q2

And VT = V1 = V2

Ceq=Q/VT = (Q1+Q2)/VT = (Q1/VT) + (Q2/VT)

Parallel Capacitors Equation:

Ceq = C1+C2+C3+ ———— +CN

The equivalent capacitance of the capacitors which are connected in parallel is equal to the sum of the individual capacitances of the capacitors in the circuit.

From the figure 4, the equivalent capacitance (Ceq) value is equal to the sum of both the capacitance values of C1 and C2, the expression is shown below.

Ceq = C1+C2

Capacitors in Parallel - Example No1:

Consider the capacitance values of the two capacitors C1 =0.2uF and C2 =0.3uF which are shown in above figure 4. Now calculate the equivalent capacitance of the circuit.

We know that the Equivalent capacitance,

Ceq = C1 + C2

Ceq =0.2uF + 0.3uF

Ceq =0.5uF

One important point to remember about parallel connected capacitor circuits, the equivalent capacitance (Ceq) of any two or more capacitors connected together in parallel will always be greater than the value of the largest capacitor in the circuit as we are adding together values. So in our example above Ceq=0.5uF whereas the largest value capacitor in the circuit is only 0.3uF.

Capacitors in Parallel - Example No2:

Calculate the equivalent capacitance across the set of two capacitors in parallel shown in figure 4.

(a) One capacitor of 0.1uF connected in parallel with 0.2uF.

(b) One capacitor of 750 nF connected in parallel with 0.5 uF.

(a) Equivalent capacitance,

Ceq = C1 + C2

Ceq =0.1uF + 0.2uF

Ceq =0.3uF

(b) Equivalent capacitance,

Ceq = C1 + C2

Ceq =750nF + 0.5uF

Ceq =750nF + 500nF

Ceq = 1250 nF =1.25uF

In the above two cases we observed that the equivalent capacitance (Ceq) value of the two capacitors connected together in parallel is greater than the value of the largest capacitor in the circuit as we are adding together values. In section (a) the value of Ceq = 0.3uF whereas the largest value capacitor is only 0.2uF. In section (b) the value of Ceq= 1.25uF whereas the largest value capacitor in the circuit is 0.5uF only.

Capacitors in parallel Summary:

The equivalent capacitance of the group of capacitors which are connected in parallel is equal to the sum of capacitances of the individual capacitors. i.e Ceq = C1+C2. Because the voltage drop across the individual capacitor is equal to the total voltage applied between the input and output terminals of the circuit. i.e. VT = V1=V2. The charges stored in individual capacitors are different but the sum of all the individual capacitor charges is equal to the total charge flows in the circuit. i.e. Q = Q1+Q2.

The charging current flow in circuit is distributed to all the capacitors in the circuit. But the total charging current is equal to the sum of all the individual charging currents of the capacitors in the circuit. i.e. iC=i1+i2 etc. The equivalent capacitance value of the group of capacitors which are connected in parallel is always greater than the value of the largest capacitor in the circuit.

REFERENCE // Electronics Hub