Light bulbs have a very simple structure. At the base, they have two metal contacts, which connect to the ends of an electrical circuit. The metal contacts are attached to two stiff wires, which are attached to a thin metal filament. The filament sits in the middle of the bulb, held up by a glass mount. The wires and the filament are housed in a glass bulb, which is filled with an inert gas, such as argon.
When the bulb is hooked up to a power supply, an electric current flows from one contact to the other, through the wires and the filament. Electric current in a solid conductor is the mass movement of free electrons (electrons that are not tightly bound to an atom) from a negatively charged area to a positively charged area.
As the electrons zip along through the filament, they are constantly bumping into the atoms that make up the filament. The energy of each impact vibrates an atom -- in other words, the current heats the atoms up. A thinner conductor heats up more easily than a thicker conductor because it is more resistant to the movement of electrons.
Bound electrons in the vibrating atoms may be boosted temporarily to a higher energy level. When they fall back to their normal levels, the electrons release the extra energy in the form of photons. Metal atoms release mostly infrared light photons, which are invisible to the human eye. But if they are heated to a high enough level -- around 4,000 degrees Fahrenheit (2,200 degrees C) in the case of a light bulb -- they will emit a good deal of visible light.
The filament in a light bulb is made of a long, incredibly thin length of tungsten metal. In a typical 60-watt bulb, the tungsten filament is about 6.5 feet (2 meters) long but only one-hundredth of an inch thick. The tungsten is arranged in a double coil in order to fit it all in a small space. That is, the filament is wound up to make one coil, and then this coil is wound to make a larger coil. In a 60-watt bulb, the coil is less than an inch long.
Tungsten is used in nearly all incandescent light bulbs because it is an ideal filament material. In the next section, we'll find out why this is, and we'll examine the role of the glass bulb and inert gas.
We'll look at what the filament is made of in the next section.
FAQs
The incandescent light bulb turns electricity into light by sending the electric current through a thin wire called a filament. Electrical filaments are made up mostly of tungsten metal. The resistance of the filament heats the bulb. Eventually the filament gets so hot that it glows, producing light.
How does a light bulb work in a circuit short answer? ›
Light Bulb
Light bulbs turn the electricity to light by sending current through a thin wire called filament. The filament is usually made of tungsten, a material that emits light when electricity is passed through it.
How does a light bulb work explained for kids? ›
In the common incandescent lamp, current is forced through a fine metal filament that has a high resistance. The energy used in overcoming this resistance produces a white heat, and the filament glows brilliantly.
How do 3 way light bulbs work? ›
For the lowest setting, one filament comes on (it might be a 50-watt filament). For the next setting, the second filament comes on (it might be a 100-watt filament). For the third setting, both come on, for (in our example) a total of 150 watts.
How do light bulbs work energy? ›
Incandescent light bulbs are devices that convert electricity into light by heating a filament, using electric current, until it emits electromagnetic radiation. As current passes through the filament, its high resistance causes its temperature to rise until it glows.
How does a simple electric bulb work? ›
When current flows through the filament of a bulb, it gets heated up and begins to glow. Thus, an electric bulb works on the principle of heating effect of electric current. Q. Bulbs with filament works on the principle of heating effect of electric current.
What makes the bulb light up? ›
When a light bulb connects to an electrical power supply, an electrical current flows from one metal contact to the other. As the current travels through the wires and the filament, the filament heats up to the point where it begins to emit photons, which are small packets of visible light.
How does a simple light circuit work? ›
An electrical circuit is composed of a source of electrical power, two wires that can carry electric current, and a light bulb. One end of both the wires is attached to the terminal of a cell while their free ends are connected to the light bulb. The electrical circuit is broken when the bulb is switched off.
How does a light switch to a light bulb work? ›
Operation of the switch
When the switch is “on,” it closes the contacts inside the switch, completing the circuit and allowing electricity to flow. This simple act of opening and closing the circuit by manipulating the switch allows lights to be turned on and off as needed.
What is bulb in simple terms? ›
1. a. : a resting stage of a plant (such as the lily, onion, hyacinth, or tulip) that is usually formed underground and consists of a short stem base bearing one or more buds enclosed in overlapping membranous or fleshy leaves. b. : a fleshy structure (such as a tuber or corm) resembling a bulb in appearance.
When the electrons flow the current generates, this current also flows throgh the bulb. Generally, an electric bulb has a thin filamemt made of tungsten which offer resistance when current flows through it and hence, the electrical energy changes into heat and light energy. This is how the bulb glows.
How does a lamp socket work? ›
Power reaches the bulb by running through the metal tab at the bottom of the socket (via the Hot wire), where the bulb sits, through the bulb, and back out the metal threads where the bulb is screwed in (via the Neutral wire), creating a circuit.
Can you replace a 3-way bulb with LED? ›
They often don't work well with LEDs, whether they are smart or dumb. And some smart LEDs have trouble maintaining radio power on medium. But that's not the only way to design a three-way lamp, and I believe that newer ones are more likely to be designed so that they will work fine with LEDs.
How does the electricity pass through the bulb? ›
There is a filament in the bulb, which has high resistance for current. Hence, when we pass the current through the filament, the filament blocks the path of the current due to high resistance and due to more and more incoming current and less outgoing current, the filament gets heated up and it starts to glow.
How does a bulb light up immediately? ›
When the electrons flow the current generates, this current also flows throgh the bulb. Generally, an electric bulb has a thin filamemt made of tungsten which offer resistance when current flows through it and hence, the electrical energy changes into heat and light energy. This is how the bulb glows.
How does light travel from a light bulb? ›
HOW DOES LIGHT TRAVEL? Light travels as a wave. But unlike sound waves or water waves, it does not need any matter or material to carry its energy along. This means that light can travel through a vacuum—a completely airless space.
How does electricity create light? ›
Turning on a light closes a circuit, which allows electricity to flow from one electric wire, through the light bulb, and then through another wire. An incandescent light bulb produces light as electricity flows through a tiny wire in the bulb, which gets very hot and glows.
