This is good website about torches.www.energizer.comThe convenience of portable light is as close as a simple button on your flashlight. But just how does a flashlight work? We’ll show you.
</b><b></b>The case is the tube that covers different parts of the torch, including the batteries and the light bulb.
This is a diagram of the torch in one piece.
<b>Contacts<br></b>Located throughout the torch there is a very thin spring of metal, making the electrical connection between the different parts, such as the batteries, the light bulb and the switch. These parts complete the circuit by conducting electricity that then hooks everything up.
</b>The flow of electricity is operated when you push the ON switch, which then gives you light. The flow of electricity is then broken when you push the OFF switch, which then turns the light off. This happens each time you press the switch.
</b> The reflector is a plastic part that is coated with a layer of aluminium that sits around the light bulb. This then redirects the light rays that allows the torch to give a steady light beam.
</b>The light bulb is the light source for the torch. In most torches the light bulb is either a tungsten filament (a very hot bulb) or a LED bulb. Both of these filaments glows when electricity flows through it.
</b>The lens is a clear plastic circle on the front of the torch that protects the light bulb. The reason there is a lens is because the light bulb is made out of glass and can easily be broken.
</b><b></b>When the torch is activated, the batteries are the power source for your torch.<b></b><b></b>