The tube that houses the parts of the torch, including the batteries and lamp (light bulb).
A very thin spring or strip of metal (usually copper or brass) that is located throughout the torch, making the electrical connection between the various parts - the batteries, the lamp, and the switch. These parts conduct electricity and "hook everything up," completing the circuit.
The flow of electricity is activated when you push the switch into the ON position, giving you light. The flow of electricity is broken when the switch is pushed into the OFF position, thus turning off the light.
The light source in a torch. In most torches, the lamp is either a tungsten filament (incandescent bulb) or a light emitting diode (solid state bulb), also known as an LED. The tungsten filament or LED glows when electricity flows through it, thus producing visible light. Tungsten is a natural element and the tungsten filament is a very thin wire. Tungsten lamps must be replaced when the tungsten filament breaks. An LED contains a very small semiconductor (diode) that is encapsulated in epoxy and this part emits light when electricity flows through it. LED's in torches are widely considered "unbreakable" and not replaced - a lifetime lamp.
The lens is the clear, plastic part you see on the front of the torch that protects the lamp, since the lamp is made of glass and can easily be broken.
When activated, the batteries are the power source for your torch.
A plastic part, coated with a shiny aluminium layer that rests around the lamp (light bulb) and redirects the light rays from the lamp to allow a steady light beam, which is the light you see emitting from the torch.