 Good morning and welcome you all, this is the video recording for the lab experiment that you people are going to conduct at your colleges. This lab experiments are part of 1000 teachers training program that is planned for December 12 to 22nd and the objective of these videos are to record the instructions of how to conduct the lab experiments. So that the coordinators at various remote centers can take help of these videos or even the participant can look at these videos and then accordingly conduct this experiment at their premises. So in this program I will mainly cover three lab experiments which are related to the photo tag modules. This lab experiment, the lab experiment number one is identifying and measuring IV characteristic of a PV module. Experiment number two is series and parallel connection of a PV modules and the experiment number three is effect of sun tracking on energy generation in a PV system. So I will first give you the theory about these lab experiments, what is the basic idea, how the experiment has to be performed and after this theory is explained here, we will also show you how to conduct the experiment with the actual setup and the same setup is going to be given to your remote center. Same setup will be available at your remote center so that you can exactly do the similar experiment and hopefully learn a lot from these experiments. So let me start explaining the experiment at number one but basically in the all three experiments PV module is the main device which you need to measure and therefore I will start with explaining the basic features and basic parameters of a PV module and once we understand those basic parameter I will show you how one can find out the characteristic of a module. So experiment number one identifying and measuring IV characteristic of a PV module. First of all the PV modules that are provided to you are basically monochrist line silicon PV module and multicrist line silicon PV module. The one way to identify between the monochrist line and multicrist line silicon module is that the monochrist line silicon module have the cells which are pseudo square in nature so typically you have this kind of arrangement. Now the cells are normally very big and typically they are cut in the smaller pieces so when the cells are cut in smaller pieces you will see one part of the cell which is looking like this. So and this is what is the case of a monochrist line silicon. Monochrist line silicon cell will look like this but if you look at the multicrist line silicon normal the multicrist line silicon cells are perfectly square or rectangular in nature again the dimension of the cells can also be very big and therefore again they are cut into smaller pieces so the smaller piece will look something like this. And this is the case for the multicrist line silicon. So the basic difference that you can see between the mono and multicrist line silicon is that in the monochrist line silicon cells the cells will be there rounded will have the round corner while in case of multicrist line the cell will be either square or rectangular and because of this arrangement because of this when the next cell is when the cells are connected in series for example if this cell is connected in series here you will have this kind of arrangement and therefore and this will continue while these cells are connected in series you will have this kind of arrangement. So what you can see is this number of cells here will have this kind of space which are empty and which is looking which will look as a white space in your PV module. And that is what identification of a monochrist line silicon but if you have the multicrist line silicon because they are rectangular in nature they can very tightly be fit into the module and you will not see the white spaces and that is identification of a multicrist line silicon. So when you do the experiment actually in your center first try to identify which module is a monochrist line module and which module is a multicrist line silicon module. Another thing is in module you will see many cells are connected in series and the reason for that is to get a higher open circuit voltage of the module and therefore normally in either monochrist line silicon or in multicrist line silicon there are 36 cells connected in series. So you will find that 36 cells are connected in series in both the cases. So second thing when you go to do the experiment you need to do is count the number of cells that are connected in series and also check the connection. So when you have the series connection of the cells basically your cells are sitting like this, cells are sitting like this. The top side of the cell where you have the metal, where you have the metal contacts is a negative side. So when the cells are like this series connection of the cells means the top side of the contact is actually connected to the back side. Similarly for the next cell the top side is connected to the back side. In the same arrangement will be continued for the 36 cells connected in a module. This will happen both for the monochrist line silicon cells. Same thing will happen also for the multicrist line silicon cells. So once you start doing your experiment first of all find out which is monochrist line which is multicrist line silicon module. Second thing find out whether there are 36 cells in both the modules or not and third thing is find out whether there is a series connection between the cells or not. So this is how you can identify a module and the series in parallel connection and monochrist line and multicrist line cells in a module. So let us now look at the characteristic of a PV module. In order to find out the characteristic of a PV module we know that a PV cell is nothing but a p-n junction diode and the characteristic of a p-n junction diode is something like this. This is the current axis, this is the voltage axis. A solar cell is nothing but a p-n junction diode under the light condition and because of the light generated current the characteristic of a solar cell is given by the blue curve. So this is your diode and this is your solar cell. So solar cell mainly operates in the fourth quadrant because the current is negative and the voltage is positive which means power is negative and because of the negative power power generation occurs. In this quadrant first quadrant where current is positive and voltage is positive your power is positive. In this case in this quadrant p is v into i positive power in this case p is minus i into v and because of this negative sign the power is generated here the power generation occurs and here in this case the power consumption occurs. So we are interested mainly in the power generation. So this part of the IV curve which is the fourth quadrant current is negative voltage is positive is the most important part of a solar cell and therefore also solar p-v module. So in practice when we draw the IV curve of a module or a cell we draw the current axis and we draw the voltage axis and this is actually drawn like this. The difference between this graph and this graph is that here the y axis is actually a negative current axis and then this is a positive voltage axis. So normally whenever you see in the textbook or anywhere else the solar cell characteristic or a module characteristic is shown like this. So normally this is what we draw. Now in this experiment the whole idea is to measure the IV characteristics of the p-v module and find out various parameters of the characteristic. Now from this diagram we can see that there are some parameters which are very clear for example this point which is the highest current which will occur at v equal to 0. So v equal to 0 means short circuit. So this is normally referred as a short circuit current. This is another interesting point this is the point when current is equal to 0 in this axis current is 0 means, current is 0 means open circuit. So this point is known as open circuit voltage of module. Other important thing is at what point your module will give you the maximum power. For example, if your module is working at this point short circuit current. So current is very high but voltage is 0 so no power is generated at this point. If your module is working here very high voltage but 0 current which means no power is generated at this point also. Similarly, if I take the various points if I take the various points and find out the current and voltage at those points. If I take the various points and find out the current and voltage at that point I will find out at what point you will get the maximum power point. So another graph if I plot the another graph on this axis so if I extend this graph like this where this is my VOC condition. So instead of current versus voltage if I draw the power p versus v if I draw the p versus v what we will find out that this graph actually goes like this. So this is my power versus voltage. So I know that very at this condition short circuit current this is 0 power at open circuit condition there is a 0 power but in between point you will get the maximum power and therefore I want to get maximum power from my module and therefore my normal operating point should be this point. So if I extend this point there so this is the let us say operating maximum point. So current at this point is given as I m that is the current at the maximum point and this point here is vm that is the voltage at the maximum point and this point itself is corresponding to pm or pmax that is the maximum power that you can get from your module. So this is what we need to find out by doing the experiments. If I give you a module of a certain characteristic your job will be to go to the terrace measure the current and voltage at various points and find out this parameters. Find out what is Isc, find out what is I m, find out what is pmax, find out what is vm and find out what is voc. Now one other important parameter is the efficiency of the module. Other important parameter is efficiency of PV module. Efficiency of the PV module can be obtained of course given by P out divided by P in. So now what is P out, P out is the maximum power that you can get from your module. So therefore efficiency can be given by P max divided by P in. What is your P max? P max is a product of I m into vm that is your product. So then you have the I m into vm and what is your P in? P in is the measured value of the power, measured value of the power density. So normally P in is given in terms of watt per meter square this you are going to measure and if you multiply by your area of the module then you will get the watt. So this you will get the ratio of watt over watt. So P in, so normally you have to also multiply by the area. So your P in will be the measured power density multiplied by multiplied by the area. What is this area? This area is the module area, so you have to get the multiplied by the area. How do you get this area? This area you, how do you get this P in that is the measured value. This value can be measured either by pyrinometer or even with the help of solar cell approximate value can be measured by pyrinometer and this reading is given in terms of watt per meter square. The actual radiation condition outside atmosphere can vary from very low radiation intensity that is 100 watt per meter square to up to 1000 watt per meter square. So that we need to find out that we need to also measure. If you can find out the V in area you can measure, IMVM you can measure, all other parameter you can measure and therefore one can also measure the efficiency. So this is another parameter. So when we want to measure the characteristic of a PV module we need to measure all these parameters. Now the question is how we can measure? So once you are given a PV module how we can measure it that I will show you now. So let us now look at the measurements how you can perform the measurements. Basically what I want to do is again, what I want to do is I want to find out this characteristic. This is my current axis and remember this is a negative current axis. This is my voltage axis. First of all it is very easy to measure the short circuit current. If you take a PV module, if you just take a PV module, so you take a PV module and the symbol of PV module is like this and there are two terminals at the back side. Let us say one is positive terminal and one is negative terminal. So if you take your ammeter and if you connect ammeter across this, so if you just connect your ammeter here like this then you are going to get a short circuit current. So it is very easy to find out this particular points. You can easily find out the short circuit current. Same thing you can also find out the open circuit. So in this condition because of the low resistance of a emitter this terminals are of the module is shorted and whatever current flow is a short circuit current. Now this is the point is called the open circuit voltage VoC. If you want to find out the open circuit voltage of the module, again what you need to do is set the multimeter in a voltmeter mode and voltmeter have a very high resistance or infinite resistance and therefore it behaves as if it is an open circuit. In this case if you connect your voltmeter across the two terminals of a module, you will actually measure this particular point, open circuit voltage of the module, fine. Now the important thing is how to find out the other points in between, how we can find out the other points in between. What are the other points? Other point is a different combination of current and voltage and we know that somewhere here you get the maximum power here you are at this point your power is 0, at this point your power is 0 but somewhere in between your power that you can get maximum. So basically what we need to do is find out the current and voltage points at various current and voltage points across the full range of power or operating point that module can operate, how to do it? So the way to do it is like this, if you can make the arrangement which is the normal arrangement that we can make is again you take a PV module. So this is your PV module, let us say this is your positive terminal and this is your negative terminal. So the device that is used to find out this point is another rheostat that you can use and we know that depending on the value of the resistance the shape of the IV curve will change. So for example, if I plot the I and V for a resistor R, it will follow basically the Ohm's law V equal to I R. So it will be a slope like this. This is may be R 1, similarly if I have another resistor it may have this kind of slope R 2, if I have another resistor it may have slope R 3 like this. So in this case assuming this is the negative current and positive voltage in this case higher the slope means lower is the value of resistance. Whereas the slope means lower is the value of resistance, basically R can be given here by delta V by delta I. When the slope is higher there is a larger change in the current and the smaller change in voltage, smaller change in voltage means lower value of R. In this case in this line there is a larger change in voltage. So this is the delta V and this is your delta I. So if we are talking about R 3, R 3 basically in this case is a larger change in the delta V, smallest change in the current and therefore, it R 3 represents higher value of resistance, R 2 represents lower value of resistance, R 1 represents even lower value of resistance. Suppose same thing is happening, suppose I find a way in which I connect a resistor across the module in such a way that like this. So basically the intersection point of a blue curve which is the blue curve which is the resistance curve and the black curve which is the module curve and the intersection point will be the operating point. What are this various line represents? The various line represents different value of resistance, various line represent different value of resistance. This point is corresponding to short circuit, zero resistance. This point is corresponding to open circuit, infinite resistance. So therefore, as I go from this point to this point to this point, my value of resistance is increasing. So therefore, what I need to do? If I connect a PV module with a rheostat where I can change the resistance from very low value of resistance almost zero ohm to very high value of resistance depending on the current and voltage, I can actually measure all this point. So coming back to here, so coming back here if I actually connect a variable resistance in this case and if I connect a meter here, then this circuit is closed but I also want to measure my open circuit voltage. So then I also connect one ohm meter here and measure this two point. So I am changing the resistance value from very low resistance so that I can get the point this one and then I keep increasing the resistance, as I keep increasing the resistance I get this point then I get this point and then I get this point. So as I am changing my resistance, I am getting this point and then higher resistance I will get this point, even high resistance I will get this point, I get this point, I get this point, this point and finally, I already I can measure already open circuit and short circuit right. So, at each point you need to measure your current and voltage which is which can be done by two two setup. So, at each point you change your resistance value measure the note the rest value of the current and the value of the voltage. Change your resistance value measure the value of current and value of the voltage, change your real state till you go from the one side to other side. So, this actually is your variable resistance that you need to have right. How many how many points you should take as many as you can ok. So, normally you should have about 10 to 20 points. So, that make sure that you do not change very large value of resistance. So, after this point you should not get this point directly right. So, you are missing this points you should get many points in between. So, for one I V characteristic there should be about 10 to 20 points that you must measure fine. How you can do what you can do after you can make a observation table? Your observation table will be like this your serial number, value of voltage value of current and value of power right. So, your serial number one can be a condition when you have the short circuit current. So, 0 voltage which is this point 0 voltage and whatever current you will measure let us say 1 ampere and the power is 0. And here you keep on registering your voltages and the power is actually product of V into I power is V into I. So, you find out the product and this you need to calculate in keep all calculating after doing this after doing this observation you can plot the graph plot the graph between current and voltage and you will find this kind of graph you also need to plot the power versus voltage and you will you have this kind of graph this current versus voltage power versus voltage you need to find out. Once you know the P max this is the maximum power point once you know the P max you can also find out the efficiency where your P max P in what is your measured power multiplied by the area of the module right. In this way you can find out all the parameters you can find out. So, suppose at a given point suppose this point is your P max suppose this point is your corresponding to P max and then the this corresponding point will be this corresponding point will be I m that is the current at maximum power point and the corresponding point will be V m that is voltage at maximum power point. So, if you do this if you do this all this measurement you can find out entire parameters of a module. So, that is the current open circuit voltage maximum power point current at maximum power point voltage at maximum power point and the efficiency. There is one more parameter that you can find out that is the fill factor and fill factor is the ratio of I m into V m divided by I s c into V o c I m into V m divided by I s c into V o c. The fill factor fill factor represent the fill of the or the squareness of the current. So, typically the fill factor for crystalline silicon solar cell will be about 70 to 75 percent. So, for example, if I have if I have two modules one is having I weaker like this another is having I weaker like this module number 1 module number 2 as you can see this module number 1 is more square. So, which means a fill factor of this module will be higher as compared to the module number 2 which is less square and definitely the maximum power point here will be lower. So, this module I is here and this module is here. So, the module number 2 will have the lower maximum power point which means lower fill factor even though the short circuit current and open circuit voltage is same fine. So, this is the basic theory of measuring the I V characteristic of a p v module and by doing this you can do the measurement. You can also cross check your measurement with what is what is given at the back side of the module. So, at the back side of the module you will find the rated value of current voltage and power and you just check the the rating that you have got that you got from your experiment how different it is from your from your actual from the rated measurement and from the rated values and your actual measurements. There are two reasons why the the values will be different. For example, P max which is the the rated the rated value will be given at actually 1000 watt per meter square. So, when you are doing when you are doing measurement you most likely the chance that you will not get 1000 watt per meter square and your P max your power that you will get a power is proportional to the input radiation right. So, if you are 8 year 1000 watt per meter square if your P max is let us say 100 watt at 1000 watt per meter square P max is 100 watt then at 500 watt per meter square your P max will only be half of this. So, that is 50 watt. So, you will get only 50 watt. So, the output power is proportional to the input power density and there is a very good chance that your input power density or the actual radiation measured during the time of the experiment will be lower than 1000 watt per meter square which is a standard phase condition. And therefore, you may measure the lower value of the power but nevertheless make the comparison at the end of the experiment. In your manual that is provided to you there are many questions there are many questions at the end of the manual. So, please try to answer those questions based on the description that I have provided here and also based on the measurement that you are going to Thank you. Hello. So, let me introduce you to the various components that can be used for the experiment lab experiment that are planned under this 1000 teachers training program. So, one important part of this lab kit is this solar PV modules. There are 4 PV modules here and this kit has arrangement to put this modules at any angle. So, one can adjust this angle to the way they want. In fact, one can make it almost vertical and the advantage of doing this vertical is that the back side of the module are available to you and you can make various connections of the module at the back side. At the same time you can also read the rated value of the modules at various current and voltage parameters. So, these are the back side of the PV modules you can see here this is the cover which can be which can be open. So, this cover can come out and now you have the 2 connections which are which are here. The small one is the diode that comes as for the protection purpose called the bypass diode, but these are the 2 basic main points across which one can do the measurement and one needs to do the measurement. Also look at the back side of the PV modules basically the characteristic that is mentioned here. So, if you look at this module this has a maximum power of 10 watt, it has a maximum power voltage V MP of 17 volt, it has the maximum power current I MP of 0.59 ampere, it has a short circuit current of 0.61 ampere, it has the open circuit voltage of 21 volt and it also mentions the maximum system voltage of 600 volt that is the maximum system voltage it can withstand. It also says that all the parameters this parameters which is mentioned here are given under STC condition which is standard test conditions of 25 degree centigrade and 1000 watt per meter square air mass 1.5 is a spectrum. So, these are the modules you can actually open all this modules and we can do the various measurement is in this. Again this setup is made in such a way that you can actually change the angle of PV modules and keep it at any angle you want. Normally the modules should be installed at the angle equal to the latitude angle of the location and depending on the place where you are in the country if your latitude is 8 degree then keep this angle at 8 degree where latitude is higher than you can keep it higher. So, this setup will make will give you the possibility of keeping at any other angle and actually accessing the modules at the back side also. Now, depending on the requirement either you can do the measurement for one single module or you can actually put two modules in series and you can do the measurement or you can put two modules in series this two modules in series and do the measurement or you can do the two modules in parallel or these two modules in parallel and you can do the measurement. So, there are various measurements that are possible in a series as well as the parallel combination of the modules. And this system, this setup of the 4 PV modules gives you all the flexibility that you want in order to characterize the PV module under various conditions, series combination parallel combination and all that. Now, in order to measure this values you need to have, you need to have the various resistances and you also need to have the voltmeter and ammeter. So, for using a voltmeter and ammeter, we are showing you the example of two multimeters. One can be used in a voltmeter mode, other can be used in a ammeter mode. So, this is one set of that you require and the other you require is the resistance. Resistance is the load that you need to connect and as discussed in theory, the resistance value from very low value of resistance to very high value of resistance. And this resistance requirement depends on the voltage and current. So, for example, the resistance follows the ohms law, sorry the current and voltage will follow the ohms law. So, if you are trying to measure 21 volt at 0.2 ampere, so 21 divided by 0.2 is your resistance and you will get about 100 ohms. So, depending on what you want to measure, for example, if you are connecting four modules in series, you are trying to measure something like about 60, 70 volt at 0.1 and 0.1 ampere current. So, your resistance value is 60 divided by 0.1 that is 600 ohms. So, then you require a of a rheostat of 600 ohms. In this case, it is thought that either you will measure one module in series, one single module or two modules in series or two modules in parallel or two modules in series, two modules in series and both of them in parallel. So, basically in all possible condition, it is estimated that you will require a total rheostat value resistance of about 200 ohms. So, you will vary the resistance from very low value short circuit condition of about 0 ohm to open circuit condition of about 200 ohms. Therefore, either you will have one single rheostat which have the resistance range from 0 to 100 or you will have a rheostat which will have the value from 0 to 200. So, let me show you that how the value of resistance changes from the low to higher side. So, if you look at this one particular case what you need to do is you need to slide this from one side to the other side. Sliding one side to other side is giving you various combination of resistances and as discussing theory you need to actually measure about 10 to 20 points. So, therefore, you need to slide slightly so that you have about 20 points. So, you have to slide slowly from one position to other position such that there are 20 points. So, let us see how much resistance value varies as you go from one side to other side. So, now this is a rheostat and rheostat has to be connected like this one point to be connected here other point is connected the backside you can see here. If you connect both this point here this will give the this point in this point here and here will give the total value of the resistance. If you connect one point here and one point here it will give the value of resistance between this point which is point connected here and this point. So, right now we are measuring the value between this two point and as this slider will move you are going to measure the higher value of resistance. So, right now I can see this multimeter in the ohms mode resistance mode. So, you can see the value of resistance is about 3 ohm. So, very low value. Now what one ohm and as I move from one side. So, that is one ohm means you are you are actually close to the short circuit point right. As we discuss in theory very low value of resistance means the your module will operate in a short circuit mode. So, now if I move the slider as you can see the value has now come down to 7.7 ohm move slightly. Now you have the 13 ohm here we move further we get the 20 ohm in this way the different position of the slider on this real state is going to give you different value of resistance. As you can see 27.5 ohm. So, basically you need to get about anything between 10 to 20 values and I suggest that there should be at least about 15 value. So, that you can actually find out your maximum power point very precisely. So, as you can go from here to here you can see the value of resistance is changing 52, 56, 57, 64, 74, 84 and if you go to the extreme position you will get the value close to what it is designed for. So, this real state is designed for 93 ohm. Now if you are going to measure a condition for example, higher voltage and lower current as I said if you want to measure if your point is at about 30 volt and 0.1 ampere. So, 30 divided by 0.1 is 300 ohm and therefore, once as real state is not going to be sufficient in that case what you can do is you can connect two of them in series and then you can connect two of them in series and you can put them together in series. So, that total 100 plus 100 you can get 200 ohm resistance. So, in your experiment either you will have one single real state of 100 ohm or you will have one real state of 200 ohm or you will have two single real state of 100 ohm each. So, you can put them in series and do the experiment. In the first experiment when you are going to measure only I V characteristic of one single module and as you can see here from the rating the maximum voltage that you can get is 17 volt and your current is going to be about 0.1 minimum that you want to measure and therefore, so your resistance requirement is well within the 100 ohm range. So, if you have one single real state you can very well characterize one single module. If you are connecting two modules three module four modules in parallel again one single real state is going to be sufficient for all the power all the data points that you want to measure, but if you want to connect two of them in series or three of them in series or four of them series then you require higher value of real state and one real state of 100 ohm may not be sufficient. So, now let us look at the now let us try to characterize the I V characteristic of a one single PV module. So, I V characteristics of single PV module we need to have the following connection here is our PV module it has a plus and minus connection this PV module is connected in series with a meter and our load our load is nothing, but a real state and this circuit is completed and in parallel we need to connect a volt meter. So, that you can measure the voltage also let us now try to make the circuit and we can measure the various data points. So, for making the connections several cables like this will be provided this cables can be used to make the series in parallel connection what we need to do is that there are the two points across which we need to measure the current and voltages. So, before we make the circuit let me show you two data points which is which we can measure without anything that is the short circuit current when the module is shorted and open circuit voltage when module is open circuit. Both of this can be measured only with the help of multimeter. So, when you put the module when you put your multimeter in the current mode when you put your multimeter in the current mode. Current mode basically low resistance of the of your multimeter and therefore, you provide the condition for the short circuit and I am going to put it this is 20. I am going to put I am going to put this in 10 ampere range as from my module character says this my maximum current which is a short circuit current is only about 0.61 ampere. So, I am not going to measure more than 0.61 ampere current. So, if I put my module multimeter in this category in this connection and if I measure the current across two points what my module will tell me is the short circuit current. So, you can see here the current that it is measuring right now is 0.11 ampere and it is showing the negative sign because the polarity is not connected. If I if we change the polarity now it is giving a plus 0.12 ampere right. So, in this way this is the short circuit current of your module. Now, same way if I change the connection here and use this multimeter in a voltmeter mode voltmeter means very high value of resistance which means I can actually create the open circuit conditions. So, if I take this lead here put this in a voltage term black one is common and then I put in 20 in about 20 volt range as per as per my module characteristic here the maximum open circuit voltage it is about 21 volt. So, I am going to measure less than 20 volt 21 volt. So, let us put now in a so this is now in a voltage voltage mode and therefore, let me measure the voltage between those two points what you can see here is voltage is 18.93 volt. Now, this is the open circuit voltage condition again by mistake if you change the polarity of connection what you will notice here is what you will notice here is a negative sign. So, here because the polarity is now change you can get the minus 18.90 volt right. So, if your polarity is not correct you will have the negative sign appearing here. So, by without any measurement you can always find out the series I am sorry you can find out the short circuit current of your module and you can find out the open circuit voltage of your module this you not only you can do for single module, but you can do the this measurement of short circuit current and open circuit voltage of combination of modules. You can do the same measurement for two modules connected in series four modules connected in series or modules connected in parallel. So, using multimeter only you can do the series and parallel connection. Now, we need to find out other data points also because we need to plot the whole I V characteristics from short circuit current to the various points to the open circuit voltage. So, we want various data point of current and voltage on the I V curve of a P V module and therefore, we need to use the rheostat and we need to complete the and we need to complete the this circuit right. So, let us let us make let us make this circuit connections for making this circuit now. So, we can use this cables you can use cables like this and we make a connection at one point. So, now the connection to characterize a single P V module is ready. So, here you can see two wires are coming one from the positive and negative one wire is going like this and it is going to this meter which is acting as a meter you can see the connection here. This is the current meter this going in series this is connected to the rheostat here and then the second wire of the cable is going back to the module. So, in this way you are connecting one circuit which is same as shown here. So, you have the module plus side coming here going to the meter and to the load rheostat and going back. Another connection is a parallel connection of a voltmeter with respect to the module. So, this multimeter here is a parallel connection as you can see here one point is connected at the one side of the load other is connected other side of the load which is again parallel connected to the module. So, you can make this connection at this two point also. So, this is the condition right now you can see here it shows 0 voltage and it shows about 0.37 ampere current which is which is corresponding 0 voltage is corresponding to short circuit current. Now, which also means that this is at the right now low resistance value. If I change this for example, I just show you if I change is see the voltage is increasing and if you go to the other extreme you will find a high value of voltage which is corresponding to open circuit. But in practice what you need to do is you need to vary this from very slowly from one point to other point and make the measurements. So, the measurements are to be made in this following. So, you need to fill this table. So, you have the serial number voltage current and power you can calculate. So, if you take the multiply the voltage and current you can actually calculate the power also. Now, here you can make this table as much as you want but minimum 10 points and up to 20 points you should actually calculate. So, from this experiment of measuring the I V characteristic of a single P V module you need to measure this kind of characteristic. So, again you can actually start taking the reading. So, take a value of current and the value of voltage. Take another point here measure the value of current and value of the voltage. As you can see the current is not changing, but the voltage is changing significantly. Second thing take another point check the value of current and value of the voltage change further value of current value of voltage. You will notice that the value of current is not changing because if you remember in the short circuit mode. So, because we are in this mode. So, here we are expecting a graph like this in this mode till we are here your current is not changing, but your voltage is changing. Your current remains constant and therefore, right now you are not observing change in current. So, you change another point your voltage change current slightly decreases 0.37 to 0.36. Change another point your voltage is now 13.3 volt current remain same. Now, you can see your current start decreasing and voltage is 15.73 current 0.34. Current is now changing 0.3 voltage is 17. So, you are approaching now close to the open circuit voltage condition. So, now your voltage will not change much, but your current will change. So, this is the point which is corresponding to your actual maximum power point and therefore, you need to take many data at this point your current is changing. So, take many close points between this category and now your current is decreasing 0.23 voltage is 18.14 current is further decreasing and by taking many parameters points you will actually come to the end of this point. So, your 0.18 0.19 ampere and 18.53 volt. Basically, when you go to the open circuit voltage your current should become 0. So, your resistance value should be open circuit voltage means your resistance value should be infinite very largely. Now, this is only 100 ohm resistance and therefore, you are not able to measure the points lower than current corresponding to lower than 0.28 because you require very large value of resistance, but you know one open circuit points. So, by taking this data now you can plot this kind of curve. So, you will get the current versus voltage you can also do the measurement calculation of power. So, you will plot the power versus voltage. So, actually you can from this point you will find current versus voltage. You will also do the same graph and you can find power versus voltage and you will find that somewhere there is a power voltage will be like this and somewhere there is a maximum power point formulas. What you also need to. So, from this measurement you can find out this parameters you can find out what is open circuit voltage short circuit current. When you will calculate the maximum power point. So, voltage at maximum power point current at maximum power point maximum power point itself there is a maximum power you are getting and then efficiency. So, your P max which is nothing, but I m times V m and your P m needs to be measured and as I said this can be measured using pyrometer or a reference solar cell will be given to you and the value of the current of the solar cell will be actually measure of a P n and module area. So, module area you can actually measure from the dimensions P n is normally given in watt per meter square and therefore, your module area should be given in meter square. So, if you have this you can also measure the efficiency you can also measure the fill factor of the module which is ratio of I m V m divided by I s C B O C. So, in this way if you perform the experiment you can find out the overall characteristic of a one single PV module. I hope this experiment is useful now once you do this experiment you can actually you can compare what is the estimated value, what is the rated value of the PV module and what is the measured value you can do the comparison and at the end of the experiment you will be able to answer many questions about a PV module and its characteristic. I hope you will learn many things from this measurement and wish you all the best for performing this experiment. Thank you.