# Solar Panel Sales Demo

How a solar panel turns sunlight into household electricity, from the layers and silicon cells to the inverter that makes it usable at home\.

By Thomas Lamontagne

Topic: Energy

[Open the interactive Jig](https://ask.jig.com/j/KhoVaNvzPmyn)

## Transcript

### 1. Sunshine on your roof

This little house makes its own electricity from daylight\. Twelve solar panels sit on its sunny, south\-facing roof, working quietly with no moving parts\. Let's look at what you would be putting up there\.

A typical home system uses about 15 to 25 panels\.

### 2. Meet one panel

Here is a single panel at one\-fifth size\. A real one is about 1\.7 metres tall and 1\.1 metres wide, roughly a door laid flat, yet only 3 to 4 centimetres thick\. The dark grid is made of silicon cells, cut in half to waste less energy\.

This panel has 108 half cells: 6 columns of 18\.

### 3. A sandwich of layers

Pull the panel apart to see its layers\. Toughened glass protects the front, and clear seals wrap the cells to keep out water and air\. A tough backsheet covers the back, and an aluminium frame holds it all together\.

### 4. Light knocks electrons loose

Sunlight arrives as tiny packets of energy called photons\. When one hits a silicon cell, it can free an electron\. An electric field built into the cell pushes the freed electrons the same way, and moving electrons are electricity\.

The blue\-black colour is a coating that stops the silicon reflecting light away\.

### 5. Cells work as a team

Thin metal ribbons link the cells one after another, so their small pushes add up to a useful voltage\. The current gathers in the junction box on the back and leaves through two cables\. Inside the box, bypass diodes let power slip around a shaded patch\.

Cells linked one after another are wired in series\.

### 6. From DC to AC

Panels make direct current, or DC, which flows one way\. Homes run on alternating current, or AC, which switches direction many times a second\. The inverter on the wall makes that change and sends power into the house, to a battery or out to the grid\.

### 7. Follow the sun

Slide the sun across the sky and watch the inverter's screen\. Power climbs towards midday, when light strikes the panels most directly, and falls to zero at night\. On a sunny day, one 400 watt panel can make about 1\.8 kilowatt hours\.

That is in the range a typical fridge uses in a day\.

### 8. Clouds and heat

Panels need light, not heat\. Under thick cloud they keep working, just with much less power\. Very hot days actually lower output a little, so a bright, cool spring day is ideal\.

### 9. Decades of sunshine

With no moving parts, panels need little care\. Most come with a 25 year warranty and lose only about half a percent of their output each year\. That is clean power from your own roof for decades\.

Today's home panels turn about 20 to 22 percent of sunlight into electricity\.