Solar panels convert sunlight into electricity through a process involving silicon semiconductor materials. When silicon is exposed to sunlight, photons free electrons that can be manipulated to flow as direct current. The solar cells use doped silicon to create an electric field that pushes electrons from the n-type to the p-type region, generating a current. An inverter is then used to convert the direct current into alternating current that can power homes and offices. Solar energy is a renewable and clean energy source that has potential to be cost-effective in countries that receive intense sunlight like Sri Lanka.

1. Normally the two forms of
Energy,Light and Heat from
Sun,refers to Solar Energy

2. Sunlight is a renewable Energy source
which does not have harmful emissions
And above all it is free
The use of Solar Energy has not been
opened up because the oil Industry
does not owe the sun

3.  “The Sun is a unique and clean
source of free power”
 On a bright sunny day,the Sun delivers more
than 1000 kWh of Energy per square meter to
Earth’s surface,
 It is better to know that 1000kWh is the
energy found in nearly 100 liters of fuel oil

4. Solar Modules as known as Solar Panels
can convert Sunlight in to usable
Energy.

6.  Solar Thermal Modules convert
Sunlight into Heat while Solar
Photovoltaic(also known as PV) Modules
turn it into Electricity
Here we talk about
Conversion of Sunlight to
Electricity

8. When Solar Panel is exposed to sunlight ,it
absorbs some of the energy in sunlight and
use it to free electrons,then they start to
flow.
When we manipulate this flow of electrons
in a uniform manner,we can have a flow of
useful direct current(known as DC)

9.  Here,we consider about Solar
panels made out of
Silicon,which is a semi-
condutor material,
 Si is somewhat special
regarding its electric
conductivity…its worth talking
about

11.  Silicon has 4 electrons in its outer energy level….
 Naturally Silicon is found in its crystalline form
,in it each Si atom is bound to another four Si
atoms by valence bonds formed using these four
electrons,pairing with other electrons from the
other Si atoms

12. At room temperature Si is not a good
conductor of electricity,so considering its
position in the periodic table,Si is doped by
using B and P and a good conductivity is
gained.
When it is B which is used to replace some Si atoms
in the crystal structure,as B has only 3 valence
electrons there is a lack of one electron to make
one of the four bonds with other 4 Si atoms,
This lack of electron is called a “Hole”….

13. And when P is used, as it has 5 electrons in the
valence shell,it has an extra electron to make a
bond
So what is gained with B is called a P-type semi
conductor and with P it is a N-type semi conductor

14. The extra electron
found in Extrinsic Si semi-conductor

15. And then we let P type and N type semi
conductor layers to contact with each
other,

16. And then,it forms an insulating layer
Between the N and P regions,making it
difficult to other
Charges to diffuse through the interface…

17. E = hf
E – Energy of the Photon
h – Plank’s constant
f – Frequency of the Photon

18.  So,when an electron is made free by a
photon,it is pushed into the N type region
by the electric field…likewise many
electrons are pushed,
 The n type region becomes more negative
while the P type region becomes more
positive…
 Now,if we can find an extra current
path,like a wire conecting N and P type
regions,all the electrons will pass through
it, making an electric current that we can
use…

20. Load Resistor
(Home/Office Appliances)

21.  Then we can pass it through any sort of resistor
or can convert it to AC
 Solar panels are more effective in direct and
intense sunlight
 So,in countries that experience intense sunlight
,using PV modules are becoming a cost-effective
way to generate Electricity

22. What is an Inverter?
 An Inverter is an electrical device
which converts Direct Current into
Alternating Current
Why Inverter?
 Earlier,AC to DC converting devices
were known as Converters,and
devices which could be made to run
backwards,converting DC to
AC,were known as Inverters

23. Centre Zero
Galvenometer

27. Net Metering…

28. The whole thing we talked about in a
simple manner

29. Above shown photo is a
set of Solar Arrays in a Solar
Power Plant …

30. Solar energy is largely used in
European region and USA ,even with
low intensity in sunlight
Sri Lanka is near the equator,and
here we have plenty of sunlight
So we are lucky enough to use them so
effectively,as we experience intense
sunlight throughout the year