11:49 PM

Solar Energy Advantages and Disadvantages

Solar Energy Advantages and Disadvantages:

What is Solar Energy?

Without the sun, living life on earth is indeed impossible. Sun as we known is a ball of fire that gives us light and heat. The energy that we receive from the sun is called as the solar energy. With the help of this energy serious problems regarding energy that is needed everyday can be solved. Solar energy means capturing the rays of the sun and storing and its heat. This heat can be converted with the help of solar panels into heat or electrical energy. When we talk about solar energy, there are two kinds of solar energy namely, thermal energy and electrical energy.

Thermal energy is something which we can find everywhere and is totally free of cost. It helps us ding our daily chores like dries things, clothes, heats water, and many other things. Water can basically be heated in two ways i.e. actively and passively. In active method, when a heating element inside the solar hot water system heats the water during hot season. In the passive method the water is pre heated and flows through a cold inlet that of a conventional electric geezer.

Talking about electric energy, the power of the sun is used to produce electricity with the help of solar cells. It can be used through a solar home system that helps in conducting electricity where there is no power supply. Apart from that it can be used a system where the electricity supplying utility is connected to the property and lastly it can be used as a backup system where there are frequent load shedding problems.

Importance of Solar Energy:

As mentioned before solar energy is required and is important for survival of life on earth. Not only human beings, plants, animals everyone requires solar energy every day. Plants require solar energy to produce oxygen, prepare food i.e. photosynthesis. Solar energy is required to produce both pure and saltwater in oceans as it is the only source of melting the frozen ice formed on the mountain caps. Apart from that the electricity which we get to run various machines is all gained from the solar energy, thus its importance and existence is very important on a planet where there is life.

Solar energy is a clean and renewable energy. Also it’s versatile and can help in producing power for watches and calculators that do not run on batteries. It’s a clean energy because it is received directly from the sun. The fossil fuels and other gas and oil that are extracted from the mines are non renewable energy. Also they are costly and cause lot of pollution. But solar energy is something that is renewable and can be used for lots of activities. Also it is available free of cost. As fossil fuels and other oils are soon going to disappear solar energy which is available in abundant should be utilized well and hence is important.

Advantages and Uses of Solar Energy:

As we know solar energy is one such energy that is abundantly available and is free of cost, let’s have a look at some of its advantages.

An energy that is totally free of cost and saves your money as the Sun is always going to be there.
It is an environment friendly energy and hence does not create pollution.
Provides electricity that is helps in producing electricity with the help of solar panels.
A silent energy provider as the solar cells do not create sounds while extracting heat from the sun and producing electricity.
Solar energy helps in reducing the electricity bill.
The solar energy system can work independently without any connection and can be utilized and installed in remote areas too where there is no sign of electricity.
Solar energy helps in decreasing the harmful gasses and does not contribute to acid rains, global warming, forest destruction and other natural disasters.
No maintenance is required for solar energy and also it does not have any specific life span
Solar energy is used for ventilating homes i.e. ceiling fans need electricity which is gained from solar energy
Solar energy can be used to boil water instead of suing water heaters you can make use of the solar energy. Though you need to spend initially you will gain good benefits out of it in future.
Solar energy can help in heating your homes and charging batteries.
It can also be used for cooking purposes by using solar oven
It can be used to heat swimming pools. Suppose you have a swimming pool outside you house you can make use of solar blanket to heat water during extreme cold seasons.
You can use solar energy for indoor and outdoor lighting at night as it will help you see the entry door and walkway clearly.

Apart from these, solar energy can be used for commercial and industrial purposes too.

Disadvantages of Solar Energy:

Solar energy can be used only during the daytime i.e. when the sun is shining bright
The solar collectors, panels and cells that are used to absorb heat from the sun are very expensive
In case of cloudy climate, there would be no signs of sun and solar energy which is difficult.
The solar batteries that are charged or needs to be charged are very heavy and require large storage space. Replacing it is also difficult.
Its low in efficiency and requires lots of land area
There is no consistency because the devices that require energy of the sun will only work if the delivery of photons is consistent.
Replacing the solar energy panels is also a very difficult job.
Installation of solar energy requires large area so that the system can provide good amount of electricity. This is a great disadvantage in places where the area is small
Pollution can be a hindrance to solar panels as pollution can degrade the efficiency of the photovoltaic cells. Clouds can also affect solar energy.
The technology that is used to create solar energy is changing from time to time and we hope it makes lives better and more cost effective

Applications of Solar Energy:

The applications of solar energy can be bifurcated into three types i.e. Power, Domestic and Agriculture. Few popular applications that can be listed under these are as follows:

Solar water heater
Tank collector
Portable solar still
Solar cooker
Solar steam cooker
Portable solar dryer
Solar PV street light

These are some applications apart from these are many and are used on daily basis for different purposes. Let’s have a look in architecture applications. Under these applications we have the heating systems, cooling systems and the ventilation systems.

Architectural Purpose:

Architecture makes use of solar energy to a great extent. Architects require equipments that are required to produce solar energy. While deigning buildings. Thus for converting the sun’s energy into solar, solar cells and panels are required. Solar energy thus needs to be integrated for designing for the home.

Industrial Purpose:

Few industries are located in places where there is no power supply. In that case solar energy can be used as it can be generated in rural areas too until there is enough sunlight coming. Solar energy is used for radio, television, micro waves etc. Apart from that is also used for transportation purposes too.

Rural Vacation Homes:

Homes that are located in rural areas do not get proper electricity. In that case solar energy can be used. The houses can be deigned to use solar energy so that the vacations can spend their holidays well even if it’s placed in a rural area.

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