What is a Discharge Lamp: Design and Working


Discharge lamp produce electricity due to the ionization of gasses. These are reliable sources of artificial light and can produce light in different colors. Discharge lamps are so popular and cheap that they are using in many places like homes, cars, and aircraft. Due to the advancement in technology these lamps have replaced with LED’s.

Design of Lamp

The discharge lamps consist of a gas tube where gas is maintained at low pressure. The gasses in the gas tube are noble gasses like argon, neon, krypton, and odium mercury amalgam.

discharge lamp

The sodium and mercury amalgam produces an arc in the tube. Two high voltage electrodes are connected at the end of the tube. Ballast(Inductor) is connected in series with an AC source to produce high voltage.

Working of Discharge Lamp

In a discharge lamp, light is emitted when the electrons collided with each other. The gas is maintained at low pressure and in order to ionize the gasses we need high-voltage.

When the high voltage is provided to the gas tube, the gasses inside the gas tube ionized. The ionized electron moves from one electrode to another. During this process, ionized electrons collide with unionized electrons and emit lights. The light can be of different colors depends on the nature of the gas.

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Types of Discharge Lamp

There are three types of discharge lamps

Low-pressure Discharge

The working pressure of low-pressure discharge lamps is less than the atmospheric pressure. Examples are fluorescent lamps and sodium lamps. These lamps have a long life than others. One advantage of low-pressure discharge is they have a long life span. The low-pressure discharge lamps require the ballast to produce high voltage. The ballast work on the principle of the inductor.

High-Pressure Discharge

In high-pressure discharge lamps working pressure is greater than the atmospheric pressue. Examples are metal halide lamps, sodium lamps, and sodium mercury lamps.

High-intensity Discharge

The high-intensity discharge lamps use an arc array to produce light. These lamps are efficient than others and have a long life. fluorescent lights. The ballast helps to build up the high voltage.


The disadvantages of the discharge lamp are

  • These lamps are costly and are being replaced by LED and CFL bulbs


The discharge lamp are using in different places

  • street light
  • Homes
  • industries
  • vehicles
  • Aircraft

we have seen the design and working of the discharge lamp, what’s your opinion about these lamps.

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