Thyratrons

Thyratrons are type of gas-filled electrical tube used in high-power applications. They are similar to triodes, but with a few key differences. A thyratron consists of a triode with a porous anode and a cathode. The anode is usually an inscription recessed into the glass tube, allowing gas to penetrate and partially fill the anode structure.

Thyratrons were first developed in the 1930s as a replacement for mercury valves in high-power applications. They were used in various fields including radar, telecommunications, and medical equipment. The key feature of thyratrons is their ability to be triggered into a high-powered conduction state by an external signal. Once in this state, the anode current is maintained by a positive feedback loop. This allows for very high current levels to be achieved in a relatively short time.

One of the main uses of thyratrons was in the control of high-power microwave generators. They were also used in early computer applications, such as the UNIVAC 1, which utilized a large thyratron-based circuit as part of its processing system. More recent applications of thyratrons include high-energy physics and medical therapies. In these fields, the ability of thyratrons to achieve high-powered, high-repetition-rate pulses has made them attractive for certain types of experiments and treatments.

However, thyratrons are generally considered obsolete and have largely been replaced by more modern technologies such as power transistors and IGBTs. The limited control and reliability of thyratrons, combined with the development of more advanced devices, has led to their declining use in many areas.