Do you know what the world’s first light bulb looked like? Did you know it wasn’t Thomas Edison who invented the light bulb ? In this article the World of Electrical shows how to recreate the first lamp invented by man and who was the real inventor of the lamp.
For a long time, man has had the need to illuminate his natural habitat. Over the years, several lighting resources were created until LED lamps and fluorescent lamps arrived.
Who created the Lamp?
Many people think that the lamp was invented by Thomas Edison, born in the year 1847 in a city in the United States called Milan. The great truth is that the first lamp was discovered by Sir Humphry Davy, around 1802, that is, 45 years before Thomas Edison was born. Sir Humphry Davy used a bank of 2,000 cells to generate an arc of light between two sticks of coal, something very similar to a large pile.
At the time of the experiment, the use of a 2000 cell battery made a lamp of this type unfeasible, but revealed that electricity could produce high-intensity lighting if there was a reliable source of energy and it was possible to reduce the wear of carbon graphite rods.
What Thomas Edison did was to perfect all the studies on the lamps studied so far, in addition to patenting the incandescent lamp as we know it today. Thomas Edison put tungsten in place of graphite, removed oxygen from the lamp’s glass bulb and added a gas to improve the brightness inside the lamp.
How to recreate an incandescent lamp
Have you ever seen a homemade incandescent lamp at an electrical fair and wondered how to recreate the same experiment? To recreate an incandescent lamp is very simple. We will use a 12V transformer, and in the output cables of this transformer we will use two alligators holding a graphite carbon graphite.
Carbon graphite is an electrically conductive material, and when we connect the transformer we have a direct short circuit in the graphite. See that the graphite glows, heating up so much that it emits light. This is the principle of the incandescent lamp .
How to recreate the world’s first lamp
To recreate Sir Humphry Davy’s experiment, it is quite different from the incandescent lamp. For our lamp to work perfectly we will need two larger carbon graphite sticks, which can be removed from two type D batteries. Be very careful when opening the battery if you are going to reproduce this experiment. There is an acid inside the stack, so always wear gloves and glasses.
After removing the rods from the piles, we drilled a hole with the same diameter as the rod in each ready-made wooden support. The wooden supports must stand without support. After drilling the hole in the wood we fit the sticks in each support leaving a larger part of the stick out.
The electrical part of the lamp is a wire connected to the back of each carbon graphite rod, which will be connected to a plug connected to a 127V socket. To apply a voltage of approximately 14V between the rods, we will need to place a shower resistor in series with a wire in the lamp circuit. In order not to burn the resistance of the shower we have to dip the resistance in a bucket full of water.
When the resistors are in series, the current that passes is the same, but the voltage is divided. In this experiment, we have two resistances in series, the shower resistance that will receive most of the electrical voltage from the network and the air resistance between the carbon graphite rods.
With the lamp plugged in, when the two ends of the carbon graphites are brought together, an electric arc is formed between the carbon graphite rods. The tips of the carbon rods are heated and the carbon evaporates, this carbon vapor in the arc is highly luminous.
Nowadays it may seem unfeasible, but this type of lamp was used for lighting after the 1880s when it was improved. A great difficulty so far is that the coal electrodes wear out, and when the space between the coals is very large, the arc dissipates and the lamp goes out.
After 1880 there were improvements that allowed the coal to adjust automatically, and several patents were created for electromechanical systems that adjusted the graphite carbon tips, mainly based on solenoids.
An interesting curiosity is that this type of lamp was used a lot in the first projectors at the beginning of the cinema. Today lighting has evolved a lot and we have many advanced technologies for lighting that have much better energy use as is the case with LED lamps. In this video from the World of Electrical, we explain what it is and how to use the LED.