What is Thyratron : Working and Its Applications

The first thyratron was derived from the vacuum tubes like UV-200 in the 1920s. These tubes include a small amount of argon gas which increases its sensitivity like a radio signal detector as well as the german LRS relay tube. Generally, Irving Langmuir, as well as G. S. Meikle of GE, is mentioned as the earliest researchers to examine controlled rectification within gas tubes in the year 1914. In the year 1928, the first and commercial Thyratron appeared. The name of the component like thyristor was taken by combining the names of thyratron as well as a transistor. Thyristors have changed these tubes in most of the low & medium power applications.

What is Thyratron?

A thyratron is one kind of tube filled with gas and it is used like a controlled rectifier as well as a high power electrical switch. These tubes handle high currents like hard vacuum tubes. Whenever the gas within the tube becomes ionized then multiplication of electron can take place. This occurrence is called Townsend discharge. The gases used in this tube mainly include xenon, mercury vapor, neon, and hydrogen. Not like a vacuum tube, these tubes cannot be employed for amplifying the signals linearly.


Thyratron Circuit Diagram

Thyratron tube is a controlled version of the neon lamp & specially designed for providing current supply to a load. The dot symbol within the circle specifies a gas fill. In the above, the thyratron permits the flow of current throughout the load in only one direction while switched by the little DC control voltage which is connected among the grid as well as a cathode.


The source of power to load is AC, which gives a sign regarding how this tube will deactivate once it’s been switched on: because AC voltage sometimes flows through a 0V condition among half-cycles, and the flow of current throughout a load which is powered by AC should also sometimes stop.

This brief flow of current among these cycles will provide the gas time of tube to cool, allowing it to go back to its regular “off” state. Transmission may start again only if sufficient voltage is applied using an AC power source & if the DC control voltage permits it. The load voltage in an oscilloscope display will look like the following waveform.

Thyratron Working Principle

The hydrogen thyratron works on the principle of switching which is achieved through transmitting from insulating neutral gas toward conducting ionized gas. This is an electrical switch that uses high peak power. By using this principle only thyratron tube will be designed to control at high-voltage using high crest current pulses as well as high recurrence rates.


An exclusive capability of this tube will make it the perfect switch for microwave sources like magnetrons as well as klystrons. In addition, these tubes are electrically robust.


The applications of thyratron include the following.

  • These tubes are high voltage and quick-acting switches. These are used in a variety of applications like laser, radar & scientific use
  • This tube is used as an electric switch.
  • This tube is used as a grid controlled rectifier
  • This tube is used like a sawtooth sweep generator in TVs as well as radar equipment.

Thus, this is all about Thyratron. From the above information, finally, we can conclude that these tubes are used in radar, laser, etc. Here is a question for you, what are the different types of Thyratron?