The Incandescent Lamp

Summary

This script delves into the history and technology of incandescent bulbs, which have been illuminating our lives for over a century. It highlights the evolution from carbon to tungsten filaments, discussing their affordability, pleasing color rendering, and direct usability without auxiliary gear. Despite their inefficiency—converting only 10% of energy into light—the script also covers the physics behind their operation, the significance of gas-filled bulbs for longevity, and the contributions of inventors like Thomas Edison, Sir Joseph Swan, and Marvin Pipkin, who advanced bulb design and light diffusion.

Takeaways

• 💡 Incandescent bulbs have been in use for over a century, starting with carbon filament lamps and evolving to tungsten filament lamps around 1910.
• 💰 These bulbs are cost-effective and known for their good color rendering, making them suitable for various settings like restaurants and homes.
• 🔌 They are simple to use, requiring no auxiliary gear, and can be directly plugged into household current without the need for a ballast.
• ⏱️ Incandescent bulbs typically have a lifespan of around 1000 hours, with some variations in longevity.
• 🔥 Despite their widespread use, incandescent bulbs are not energy efficient, converting only about 10% of energy into light, with the rest being wasted as heat.
• 🔬 The principle of incandescence involves passing current through a filament, causing it to heat up and emit light and infrared radiation.
• 🏺 The filament is sealed within a glass bulb, which can be vacuum-sealed or filled with an inert gas like argon to prolong the filament's life and prevent it from burning out quickly.
• 📈 Gas-filled bulbs improve efficiency and lifespan, and also reduce the blackening of the glass, maintaining better light output over time.
• 🤝 Both Thomas Edison and Sir Joseph Swan independently developed early incandescent bulbs, each contributing unique designs and bases.
• 🛠 William D. Coolidge was instrumental in developing ductile tungsten, which is crucial for filaments and electrodes in various types of lamps.
• 🌀 Irving Langmuir's innovation of gas-filled incandescent bulbs and coiled tungsten filaments significantly increased the efficiency of these lamps.
• 🌫️ Marvin Pipkin invented frosted and soft light bulbs, which reduce glare and diffuse light with minimal loss of light output.

Q & A

What are the two types of filaments used in the development of incandescent bulbs?

The two types of filaments used were carbon filament lamps initially, followed by tungsten filament lamps around 1910.

Why are incandescent bulbs considered good for color rendering?

Incandescent bulbs are good for color rendering because they give a nice color rendering, making objects lighted by them look good, which is why they are excellent for restaurants and houses.

What is the main disadvantage of incandescent bulbs in terms of energy efficiency?

The main disadvantage of incandescent bulbs is their low energy efficiency, as only about 10% of the energy is converted into light, with the rest being wasted as heat.

How does the principle of incandescence work in incandescent bulbs?

Incandescence works by passing current through a filament, which heats up due to its resistance, creating photons (light) and radiant heat energy (infrared energy).

Why are incandescent bulbs filled with gas like argon or a mixture of argon and nitrogen?

Incandescent bulbs are filled with gas to exert pressure on the filament during operation, which helps it last longer, run at higher temperatures, produce more light efficiently, and reduce blackening of the glass.

What is the significance of the vacuum in the early Mazda lamps?

The vacuum in early Mazda lamps was used to keep the filament away from the air, preventing it from burning out quickly due to the high temperatures it operates at.

Who were the two inventors credited with the development of the incandescent bulb, and what were their contributions?

Thomas Edison from the USA and Sir Joseph Swan from England are credited with the development of the incandescent bulb. They both had unique contributions to bulb and filament designs, and base types.

Who developed ductile tungsten, and how has it impacted lighting technology?

William D. Coolidge developed ductile tungsten, which has been instrumental in the development of not only incandescent lamps but also fluorescent and HID lamps, as they all rely on ductile tungsten for filaments or electrodes.

What was Irving Langmuir's contribution to the efficiency of incandescent bulbs?

Irving Langmuir contributed to the efficiency of incandescent bulbs by inventing the gas-filled incandescent bulb and the idea of tightly coiling the tungsten filament, which made the bulbs more efficient.

Who invented the inside frosted and soft light bulbs, and what was the purpose of these inventions?

Marvin Pipkin invented the inside frosted bulbs to reduce glare and the soft light bulbs, which are coated on the inside with silica to diffuse the light with minimal light output loss.

What is the typical lifespan of a tungsten filament incandescent bulb?

The typical lifespan of a tungsten filament incandescent bulb is about 1000 hours, although some bulbs may have longer or shorter lives.

Outlines

00:00

💡 Incandescent Bulb Evolution and Principles

The paragraph discusses the history and characteristics of incandescent bulbs, which have been in use for over a century. Starting with carbon filament lamps and evolving to tungsten filament lamps around 1910, these bulbs are praised for their affordability, pleasing color rendering, and simplicity, requiring no auxiliary gear for operation. Despite their decent lifespan of about 1000 hours, they are criticized for their low efficiency, with only 10% of energy converting to light while the rest is wasted as heat. The working principle involves passing current through a tungsten filament sealed within a glass bulb, which heats up and emits light and heat. The use of gas-filled bulbs extends their lifespan and efficiency by applying pressure on the filament and reducing blackening of the glass. The contributions of Thomas Edison, Sir Joseph Swan, and William D. Coolidge in the development of bulb designs and ductile tungsten are highlighted, along with Irving Langmuir's innovation of gas-filled bulbs and coiled filaments for increased efficiency.

05:16

🌟 Innovations in Incandescent Bulb Design

This paragraph focuses on Marvin Pipkin, a significant figure in the evolution of incandescent bulbs. Pipkin is credited with inventing frosted bulbs that reduce glare by having an etched interior surface, a design still produced by some companies. Additionally, he developed soft light bulbs, which are coated with silica on the inside to diffuse light with minimal light output loss, typically around 3%-5%. These innovations represent some of the last major advancements in incandescent bulb technology, enhancing user comfort and light quality.

Keywords

💡Incandescent Bulb

An incandescent bulb is a type of lighting technology that uses a wire filament heated to a high temperature by an electric current, causing it to glow. This is the central theme of the video, as it discusses the history, advantages, and disadvantages of incandescent bulbs. The script mentions the evolution from carbon filament lamps to tungsten filament lamps, highlighting the bulb's development over the past century.

💡Tungsten Filament

Tungsten filament refers to the thin wire inside an incandescent bulb, made from the metal tungsten, which is heated to emit light. The script explains that tungsten is used because of its high melting point, allowing it to withstand the high temperatures required for incandescence without melting. It is a key component that has been in use since around 1910.

💡Color Rendering

Color rendering is the ability of a light source to show the true colors of objects. The script praises incandescent bulbs for their excellent color rendering, meaning they make objects look good under their light, which is beneficial for settings like restaurants and homes where visual appeal is important.

💡Auxiliary Gear

Auxiliary gear refers to additional equipment needed to operate certain types of lighting. The video mentions that incandescent bulbs do not require auxiliary gear like ballasts, which are necessary for some other types of lighting to function. This makes incandescent bulbs simpler and more convenient to use, as they can be plugged directly into household current.

💡Incandescence

Incandescence is the process by which a material emits light as a result of being heated. The script describes the principle behind incandescent bulbs as a simple form of incandescence, where the tungsten filament is heated until it glows, producing both visible light and infrared energy.

💡Vacuum

A vacuum is a space devoid of matter, including air. The script explains that early incandescent bulbs used a vacuum inside the glass bulb to protect the filament from burning up due to the high temperatures it operates at. This was an essential innovation for the longevity of the bulbs.

💡Gas Filled

Gas filled refers to the practice of introducing an inert gas like argon into the bulb. The script discusses how filling the bulb with gas extends the life of the filament, allows it to run at higher temperatures, and improves the efficiency of the bulb without reducing its lifespan. This innovation also helps to prevent the blackening of the glass.

💡Blackening

Blackening is the discoloration of the glass bulb due to the deposition of tungsten from the filament. The script mentions that gas-filled bulbs reduce blackening, which can occur in vacuum bulbs and diminish the light output over time. This is an important aspect of maintaining the bulb's performance.

💡Ductile Tungsten

Ductile tungsten is a form of tungsten that can be drawn into thin wires, which is essential for making filaments. The script credits William D. Coolidge for developing ductile tungsten, which is used not only in incandescent lamps but also in other types of lighting, highlighting its significance in the lighting industry.

💡Coiling

Coiling refers to the process of winding the filament into a compact spiral shape. The script explains that coiling the tungsten filament makes it more efficient by reducing its length and increasing the surface area that can emit light. This innovation was a significant step forward in the design of incandescent bulbs.

💡Inside Frosted Bulbs

Inside frosted bulbs are a type of incandescent bulb with a frosted or etched interior surface. The script mentions Marvin Pipkin's invention of these bulbs, which reduce glare without significantly reducing light output. This feature enhances the comfort and aesthetics of lighting in various settings.

Highlights

Incandescent bulbs have been in use for over 100 years.

The transition from carbon to tungsten filament lamps around 1910.

Advantages include low cost and good color rendering.

Suitable for use in restaurants and homes due to their aesthetic lighting.

No auxiliary gear needed, can be plugged directly into household current.

No ballast required, reducing energy losses.

Average bulb life is about 1000 hours.

Inefficiency as only 10% of energy is converted to light, the rest to heat.

Principle of incandescence involves heating a filament to produce light.

Tungsten filaments are used due to their high resistance and durability.

Bulbs are sealed to prevent rapid burning of the filament in air.

Gas-filled bulbs increase filament life and efficiency.

Gas inside the bulb reduces blackening of the glass.

Thomas Edison and Sir Joseph Swan developed incandescent bulbs independently.

Different bulb bases developed in the USA and England.

William D. Coolidge developed ductile tungsten for Mazda lamps.

Irving Langmuir contributed to the efficiency of gas-filled incandescent bulbs.

Coiling the tungsten filament increased efficiency.

Marvin Pipkin invented frosted and soft light bulbs for reduced glare and diffused lighting.

Transcripts

Here is an incandescent bulb,

they have been with us over 100 years

we started out with first carbon filament lamps

and then around 1910 tungsten filament lamps

and we are still with tungsten filament lamps

and they have several advantages, several disadvantages.

Advantages are that they are inexpensive and they give a nice color rendering

objects lighted by them look good so they are excellent for restaurants,

houses, things like that.

They don't need any auxiliary gear

which means you can plug them straight into the household current

and you don't need a ballast so there are no loses from the ballast

and they have a decent life, some of them are longer life then others

but most are about 1000 hours.

the disadvantages are they are not the most efficient light source,

in fact only 10% of the energy makes light the rest makes heat.

How it works its a very simple principle incandescence,

you have a material whether be carbon or tungsten, tungsten is a metal,

that you place inside of a glass bulb and you seal them either in a vacuum

or you make a vacuum and then you fill the space with a gas like argon

or a mixture of argon and nitrogen and you pass current through this material

which is really a fine wire and it heat up, it's a resistor, another words,

the current can't pass through easily, so when the current tries to pass through the wire

it's forces his way through and it heats up the wire trying to do it

and in that case it creates photons which is light also why an also it gives off radient

heat energy as well which is actually another form of light, infrared energy.

The reason why the filament is sealed in a bulb is because if it were exposed

to the air it will burn up in a few seconds because it runs at such high temperatures,

so by put the vacuum in the bulb like the old Mazda lamp has,

it keeps the filament away from the air so it doesn't burn out

but with today light bulbs, you fill the bulb with gas

and the gas exerts a pressure on the filament when is in operation

and makes it last longer and it can run at a higher temperature

and thus produce more light more efficiently without shortening the life

of the bulb so that's the object of putting the gas inside the bulb,

plus it reduces blackening of the glass

because blackening goes to the highest part of the bulb.

if its base up will be here if is horizontal it will be here and if is base down

it will be here, so that the whole bulb doesn't blacken

like a vacuum bulb does and the bulb will maintain better light output

throughout life which is another advantage of gas filling.

Thomas Edison from USA and Sir Joseph Swan from England

they both hit on the idea of a high resistance filament at the same time

neither copied either's idea, both had their unique contributions

as far as bulb designs, filament designs, bases, etc...

in fact in England he light bulb ended up as being a bayonet base pushed in and turn base

which they still are today and then USA it was the familiar screw base

so they had their own individual developments

and then a little later on in history

William D. Coolidge was instrumental developing ductile tungsten

for the Mazda lamps which is still in use to these very day and not just

incandescent lamps rely on it but incandescent, fluorescent, all kind of HID lamps

because they all rely on ductile Tungsten for either filaments or electrodes.

so he developed ductile tungsten wire and then around the same time

Irving Langmuir came about with the idea of the gas filled incandescent bulb

and of course that was a great contribution for increasing efficiency

he also came up with the idea of [tight] coiling the tungsten filament

instead of the early bulbs were the straight wire filament

they coiled the filament in to a compact unit and eventually by the the 30s

they were double coiling them which is what this bulb has.

And by coiling the filament twice, it makes it very short and much more efficient.

And another person that is very instrumental, who is one of my favorites

is Marvin Pipkin he the fellow that invented both the inside frosted bulbs

that were etched on the inside to reduce glare from the bulbs,

which some companies still manufactures to this day and the soft light bulbs.

And they are coated on the inside with silica, to defuse the light;

With only about 3% loss of light output, 10% at the most in some lamps

but usually is about 3%-5% so that was probably

one of the last greatest developments in the incandescent bulb

that is still with us today.