What is an Arc Lamp : Working Principle and Its Advantages

The first arc lamp was invented by Sir Humphry Davy in the early 1800s, This lamp was designed with two carbon electrodes and 2,000 cells battery to generate the arc across a 4-inch gap in between two electrodes in air. So this lamp was used in movie projectors, searchlights, etc. Nowadays, the most widely used lamps are gas discharge lamps. This lamp uses two carbon rods to generate light by high current sparking between them. In the late 1870s, suitable electric generators are available & also these were started using practically. An arc lamp like Yablochkov candle was invented by the Russian engineer namely Pavel Yablochkov. He has used this lamp in street lights in Paris as well as other European cities.

What is an Arc Lamp?

Definition: An electric lamp that is used to generate light by making an arc between the spaces of two electrodes when electrical energy is supplied. The energy comes from the heated electrodes and from the arc. These lamps are used where high brightness is necessary like searchlights, food lights and large film projectors.


There are different types of arc lamps available based on the application like Carbon, Flame, Magnetic, High-Pressure Xenon, High-Pressure Mercury, Metal Halide and these are used in Laser Pumping. The diagram of the Arc lamp is shown and discussed below.

Working Principle of Arc Lamp

The working principle of the Arc lamp mainly depends on the light output as well as stable electrical power; however, it is also feasible to understand the forms of quasi-continuous operation. However, the lifetime of the lamp can be reduced by thermal cycling. This problem can be reduced through specially used electrode designs. One of the best examples of this is a carbon arc lamp.

The electrodes in these lamps are in contact with the air so that a low voltage can cause to get an arc. After that, the electrodes are gradually separated. Consequently, the current within this will get heated & the arc can be maintained among the electrodes.


By using the heating process, the carbon electrodes tip can be evaporated. The high brightness light can be generated through the carbon vapor within the arc as it is highly luminous. The color of the generated light mainly depends on the time, temperature as well as its characteristics


In gas discharge (GD) lamps, the arc can be generated within the space of the electrodes. Space is packed with any static gas. The arc can be generated through the ionization of the exact gas. Both the gas & electrodes are covered together with a glass tube. Whenever the high voltage power supply is given to electrodes, then the atoms within the gas will face an incredible electric force so that the atoms will split into free electrons & ions. Therefore the process of ionization takes place.

The atoms which are split into atoms & ions will travel in different directions. These charges will collapse with the electrodes. Thus, energy can be generated in the light/flash form which is known as an arc. The formation of the arc can be done through the process of discharging. Therefore it is called discharge lamps.

The arc lamp’s name, as well as the name of the emitted color, depends on the atomic structure of the inert gas within the glass tube. The range of typical temperature is 3000oC/5400oC. The xenon type lamp generates white color which is used widely because it is related to natural daylight. The neon type lamp generates red color whereas the mercury type lamp generates bluish color. The inert gasses combination will also give an extra light spectrum with a wide range of wavelengths.

Arc Lamp Advantages

The advantages of arc lamps include the following.

  • It generates Bright light
  • It is used to generate lighting for a large length of streets or inside of the large factory.
  • These lights are cheaper than street lights, oil or gas lamps.


The disadvantages of arc lamps include the following.

  • The electrodes in the lamp need to replace after a short period of time. So this is a full-time job for the operators.
  • These lamps generate dangerous rays like UV-A, UV-B & UV-C
  • When the light burns, then it generates flickering & buzzing sound.
  • It will damage when he sparks or excessive heat emit

Applications of Arc Lamp

The arc lamp applications include the following.

  • Camera flashlights
  • Therapeutics
  • Lights at floods & outdoor
  • Microscope lighting
  • Blueprinting
  • Endoscopy
  • Searchlights
  • Projectors in cinema halls
  • Early motion pictures
  • Followspots


1). What is arcing in an electrical circuit?

When an electric current supplies among two conductors or circuit through the air

2). Is the arc lamp still used today?

Yes in some specialized applications where high-intensity light is required.

3). Why was the arc lamp important?

Arc lamp is important because of its extreme brightness in a large area

4). Is lightning an arc flash?

Lightning is an arc flash otherwise electrical explosion

5). What is the arc voltage?

When the voltage appears across the contact throughout the period of the arcing period once the flow of current is maintained within an arc form.

6). What is the application of an arc lamp?

It is used in street lamps and lighthouses

7). How an arc is generated?

It is produced between two electrodes like anode & cathode as they are in contact to begin the current flow and after that divided through a small distance.

Thus, this is all about an overview of the Arc lamp and the main function of this lamp is to generate light through an electric arc. This lamp includes two electrodes that are separated with gas and the name of this lamp is taken from the type of gas used within the arc. The arc generates light through high current sparking between two electrodes. Here is a question for you, what are the types of arm lamps?