How does a flashlight works

How Does a Flashlight Works

Before even going to the working of the flashlight, we should understand the part of the flashlights. Flashlight is comprised of 7 main parts and will discuss all these now and then move to how a flashlight works. You can check out the website for more details.


Case is nothing but a tube light thing that houses all the parts a flashlight like lamp and batteries.

flashlight like lamp


This can be either a metal strip or very thin spring. This is placed throughout flashlight and this makes the actual electrical connection between all other parts like lamp, batteries, and switch. This is the part which hooks up everything and conducts electricity by completing the  circuit.


Switch is required to activate the electricity flow. When you push this switch to the on position, it provides light. When switch goes off, electricity flow is broken and this results in turning off the light.


This is a plastic part in the flashlight that has aluminum coating. This is placed around the lamp and this helps in redirecting the rays. This also makes sure the study light beam.


This is the light source in the flashlight. In most of the flashlights, this is a light emitting diode or tungsten filament. This will glow when the electricity starts flowing and it results in visible light. Tungsten is nothing but a natural element and it is really thin. We should think of replacing Tungsten lamps when this filament breaks. But in case of LED lights it is a semiconductor that comes with encapsulation in epoxy. LEDs are popular as unbreakable lamps and usually there is no need to replace them and can be used for lifetime.


This is nothing but the plastic part that is present on the front and it is very clear and helps in protecting the lamp. This is needed since lamp is made of glass and with hard exposures it can easily broke.


This is the power source for your flashlight.

How it Works?

Let’s consider that switch of the flashlight is in ON position. Now, this results in making the contact between the contact strips inside. This leads to flow of electricity. The electricity is of course powered from the batteries.

We should understand that in a flashlight, batteries are connected so that the electricity is made to flow from positive to negative electrodes. The small spring present at the top gets connected to the contact strips.

This contact strips should run down till the bottom of the battery and it should make the connection with the switch. There should be one more flat contact strip that is present on one side of the switch which is responsible for lighting up the lamp. This is the one that make the electrical connection.

How flash Light Works

There will be one more part that connects with the lamp and positive electrode and this completes the electrical circuit and that is needed for flow of electricity.

When activated using the switch, the lamp begins to glow and it produces the visible light. Light is adequately reflected using the reflector present around the lamp. Reflector is useful in redirecting the light.