How Does a Flashlight Work?

How Does a Flashlight Work

A flashlight is a very crucial tool to have with you as you travel or carry out your daily practices. You never know when you will need it and having it handy is a great advantage. Sometimes, blackouts take place and you might find yourself in great danger of stumbling if you don’t see where you’re going. But with a small source of light like that of a flashlight, it can help you illuminate your path and stay safe. Even though a flashlight is very important, some people don’t know how it functions.

Actually, making a flashlight is very easy as long as you know which part to place where and how to connect them to complete the circuit. You will learn more about how a flashlight functions as you read on…

How the flashlight works

The moment the switch of a flashlight is pressed on, it immediately creates contact between two contact strips, which in turn start a flow of electricity, powered from the battery. The batteries are connected in a particular manner that electricity runs in between the positive and negative electrodes of the battery. The batteries lie on top of a little spring that is connected to a contact strip. The contact strip is placed in such a way that it runs down the length of the battery case and creates contact with one side of the switch. Besides this strip, there is another flat contact strip on the other side of the switch, which runs to the light bulb, giving an electrical connection. Furthermore, there is another section connected to the light bulb that creates contact with the positive electrode of the battery, hence finishing the circuit to the light bulb and completing the creation of electricity.

If it is sparked off by electricity, the LED or tungsten filament inside the light bulb starts to emit a steady light which is very visible. The light reflects off of the reflector which is placed around the light bulb or lamp. This same reflector redirects the light rays from the lamp, forming a stable beam of illumination, which is the light you see coming from the torch. To prevent the glass on the light bulb from being broken, a clear lens is placed on the light.

Finally, in the situation where you press the flashlight switch in the off position, the two contact strips are physically disengaged and the way of the electrical current is broken, hence stopping the creation of light and turning your torch off. For this entire process of switching the flashlights on/off, all the parts of the flashlights should be well connected and put together for it to happen. To know more how the flashlight works, you can view some of the parts and which roles they play as follows:

What the circuit is made of?

The circuit is made up of several points and sections through which electricity passes to allow the torch to light or be switched. The parts of the circuit include: resistor, battery, capacitor and light bulb or lamp.flashlight working principle

A resistor plays a huge role when it comes to controlling voltage and current in any circuit. Just like its name states, a resistor resists the current. If you have ever attempted to connect a battery directly to a bulb without a resistor, then by now you should have realized that the bulb becomes hot and diminish after a short period. So, the current still flows but it’s too much for the bulb to handle. The resistor functions by allowing just adequate current to reach the bulb.

This is similar to a battery but with less capacity. A capacitor is a gadget for keeping an electric charge, made up of a pair or more conductors. It is normally utilized to reduce noise, or make the supply of the power of a circuit to be very stable.

Light emitting diode
In the past, people used flashlights with filaments instead of LED bulbs. A light emitting diode is a new technology. The LED allows the current to pass through just in on direction. These can be found in flashlights and as well in mobile phones, too. Their job is to emit light. The LED bulbs replaced incandescent bulbs. When you switch on a torch, a current passes through the LED with the assistance of the circuit, then, it unleashes energy in the form of photons. These photos come to a visible wavelength and we are in a position to view the light from the LED bulb.

Parts of a flashlight

The parts of a flashlight are not new as most of you are already aware of them. But it’s good if we elaborate on them a bit and explain their functions.

  1. Case – this is the part that houses all the flashlight components. These include batteries, lamp, circuit, switch, pocket clip, reflector, o-ring and all the other parts. Usually, it is durably made and compact in design. It can be made of metal like aluminum or steel. Some are made from hard plastics while others from composite material. It all depends on the needs of the user. They also vary in size. Keychain flashlight is a good option if you are looking for small size light.
  2. Contacts – this is a very vital section of the flashlight. It is a thin strip of metal normally made of brass or copper. It is also located in the entire flashlight, creating the electrical connections between the different parts of the light such as the light bulb, batteries and switch. These sections of the torch conduct electricity and complete the circuit.
  3. Switch – the switch is used to turn the light on/off. When you press the switch on, the flow of electricity starts to take place, thus providing you with light. When the switched is turned off, the flow of electricity is broken, which turns off the light.
  4. Lens – since the light bulb or lamp is made of glass, it can be broken very easily. Due to this, the lens is placed in front of the bulb to protect the lamp. Lens are usually made of clear plastic materials that light passes through without any issue.
  5. Reflector – this is the plastic part of the torch and it is coated with a shiny aluminum layer that rests around the led bulb or tungsten filament bulb to provide a firm light beam, which is the light you see coming from the torch.
  6. Lamp – this is also known as a light bulb. It is also the light source in any flashlight. A good number of flashlights have light emitting diode or tungsten filament which some people refer to an incandescent bulb. So, when electricity flows through the bulb, it lights. Tungsten bulbs can be replaced when the filament breaks. The LED bulb is made up of a small semi-conductor that is encapsulated in epoxy and this section emits light when electricity flows through it. The LED bulbs are normally durable and almost unbreakable.
  7. Batteries – this is one of the most vital parts of a flashlight. Actually, it is the source of power for the light. AA, AAA or 18650 batteries are popular.

If you have been wondering how a simple flashlight works, now you know. A flashlight is an important device that every person should have as their EDC item. It functions through a simple process as explained from above. You can now go ahead and get different flashlight parts and assemble your own simple light if you like. Also, hope you now understand how a flashlights circuit is completed.


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