A thyratron is a gas-filled triode that acts as a high-speed, high-current switch. When a trigger pulse is applied to the grid, the thyratron conducts a large current from anode to cathode through the ionized gas. Once triggered, it continues conducting until the anode current drops to zero. Thyratrons are used to switch very high voltages and currents in pulsed power systems, radar modulators, excimer laser triggers, and particle accelerator pulse circuits.

An ignitron is a mercury-arc rectifier and switch that uses a small ignitor electrode to initiate a mercury arc, enabling it to carry very high currents (thousands of amperes). Ignitrons are used in resistance spot welding controls, large motor drives, and pulsed power applications where very high currents must be switched. They have been largely replaced by modern thyristors in new designs but remain in many legacy industrial installations.

Where are thyratrons used today?

Despite the availability of modern solid-state switches (IGBTs, SCRs), thyratrons remain in use in applications requiring: very fast switching (nanoseconds to microseconds), very high peak currents (thousands of amperes), very high voltages (tens of kilovolts), or where the legacy system design makes replacement difficult. Current applications include excimer laser trigger circuits, radar pulse modulators, particle accelerator trigger systems, electromagnetic compatibility (EMC) test equipment, and electromagnetic pulse (EMP) simulators.

Product Category

Electronic Components

Specialty vacuum and gas-filled devices: thyratrons, ignitrons, vacuum interrupters, high-vacuum rectifiers, and specialty switching components. Critical for pulsed power systems, medium-voltage switchgear, industrial controls, and legacy equipment maintenance.

Thyratrons

A thyratron is a gas-filled electronic switch capable of handling extremely high peak currents and voltages with very fast switching times. The gas fill (hydrogen, deuterium, or xenon) ionizes when triggered, creating a low-impedance conduction path. Thyratrons are characterized by:

Peak current: 100 A to 100,000 A
Peak voltage: 1 kV to 100 kV
Switching speed: 10 ns to 1 μs rise time
Operating temperature: Cathode heated to 900–1100°C
Types: Hydrogen thyratron, deuterium thyratron, xenon thyratron

Hydrogen thyratrons offer the fastest recovery time and are preferred for repetitive pulse applications (excimer laser triggers, radar). Deuterium thyratrons have similar performance with improved lifetime. Xenon thyratrons handle higher average power with slower recovery.

Ignitrons

An ignitron is a mercury-arc rectifier and controlled switch filled with liquid mercury. When the ignitor electrode initiates a mercury arc, the device conducts very high currents with low forward voltage drop. Features:

Peak current: 1,000 A to 100,000 A
Average current: 10 A to 500 A
Voltage: Up to 15 kV (inverse)
Application: Resistance welding controls, large rectifiers, pulsed power

High-Vacuum Rectifier Tubes

Thermionic vacuum rectifier tubes convert AC to DC in high-voltage power supplies. While largely superseded by solid-state rectifiers in new designs, vacuum rectifiers remain in service in legacy audio equipment, vintage radio transmitters, and some specialized high-voltage power supplies. PartnerTubes stocks types from 5Y3 to GZ34 and industrial high-voltage rectifiers.

Vacuum Interrupters

A vacuum interrupter is a sealed vacuum enclosure containing two electrical contacts — one fixed, one movable. When the contacts open under load, the arc formed quenches rapidly in the vacuum environment (at pressures of 10⁻⁶ torr or lower), enabling reliable interruption of medium-voltage AC circuits. Key specifications:

Voltage: 3.6 kV to 40.5 kV (medium voltage switchgear classes)
Current: 400 A to 3150 A (continuous); up to 63 kA (short-circuit breaking)
Long service life: 10,000–30,000 switching operations
Applications: Circuit breakers, contactors, load break switches, reclosers

PartnerTubes supplies vacuum interrupters including Czech-manufactured VS and VO series (VS104, VS103D, VS704, VS1016, VO604) and compatible types for replacement in medium-voltage switchgear.

Specialty Gas-Filled Tubes

A range of specialty gas-filled devices for specific applications:

Spark gaps: Triggered and untriggered for overvoltage protection and pulsed power switching
Krytrons: Ultra-fast gas-filled switching tubes for precision timing circuits
Dekatrons: Counting tubes for vintage instrumentation maintenance
Nixie tubes: Numerical indicator tubes for vintage display restoration
VR/regulator tubes: Voltage reference and regulation in legacy equipment

Thyratron Specifications Overview

Type	Gas Fill	Peak Current	Peak Voltage	Recovery Time	Application
Hydrogen thyratron	H₂	100–5,000 A	2–30 kV	100–500 μs	Radar modulator, excimer laser trigger
Deuterium thyratron	D₂	100–10,000 A	2–50 kV	100–500 μs	Radar, pulsed power, accelerator trigger
Xenon thyratron	Xe	1,000–100,000 A	5–100 kV	1–10 ms	High-energy pulse discharge, welding
Pseudospark switch	H₂/D₂	Up to 100,000 A	Up to 50 kV	Microseconds	EMP simulation, pulsed power

Stocked Thyratron Part Numbers

Part Number	Manufacturer	Type	Notes
51TR50	TESLA	Hydrogen thyratron	High-voltage pulse switch
52TR50	TESLA	Hydrogen thyratron	High-voltage pulse switch
TR1-15/20	TESLA	Hydrogen thyratron	15 kV / 20 kA
12QR205	TESLA / ITT	Hydrogen thyratron	Radar modulator duty
15QR40	TESLA / ITT	Hydrogen thyratron	Radar modulator duty
TQ61	EEV / TESLA	Hydrogen thyratron	Pulsed power, radar
UA5A	Soviet	Thyratron	High-energy discharge
S15/40i	STC / Brimar	Hydrogen thyratron	Pulsed power switching
TGI1-500/16	Soviet	H₂ thyratron	500 hV / 16 kA peak
TGI1-1000/25	Soviet	H₂ thyratron	1000 hV / 25 kA peak
TGI2-400/16	Soviet	H₂ thyratron	Dual-gap, 400 hV / 16 kA

These are examples of stocked types. Contact us with your part number — we cross-reference thousands of thyratron types from EEV, Perkin-Elmer, Richardson, TESLA, and Soviet manufacturers.

Applications

Pulsed Power Systems

Thyratrons and spark gaps as main switches in Marx generators, pulse-forming networks, and capacitor bank discharge systems.

Radar Modulators

Hydrogen and deuterium thyratrons as line-type modulator switches for pulsed radar transmitters, providing the high-voltage, high-current trigger pulses that drive magnetrons and klystrons.

Excimer Laser Triggers

Thyratrons to switch the high-voltage discharge that excites the laser gas mixture in excimer laser systems for lithography and medical applications.

Resistance Welding

Ignitrons for precision timing and current control in resistance spot welding equipment used in automotive and manufacturing.

Particle Accelerators

Thyratrons and spark gaps as trigger switches for beam-kicker magnets, extraction systems, and pulse-power circuits in synchrotrons and linacs.

Legacy Equipment Maintenance

Replacement vacuum rectifiers, VR tubes, and specialty gas-filled components for maintaining vintage and long-lived industrial equipment.

Frequently Asked Questions

What is the modern replacement for a thyratron?

In many applications, thyratrons have been replaced by modern solid-state switches including: IGBTs (Insulated Gate Bipolar Transistors) for medium-voltage applications; SiC MOSFETs for higher voltage and speed; and series-connected IGBT or MOSFET stacks for very high voltages. However, when switching requirements demand nanosecond rise times, peak currents above 10,000 A, or peak voltages above 50 kV, thyratrons or pseudospark switches may still be the only practical solution. PartnerTubes can advise on both tube and solid-state alternatives.

Do you supply thyratrons for radar systems?

Yes. PartnerTubes supplies hydrogen and deuterium thyratrons for use as line-type modulator switches in pulsed radar systems. We cross-reference to equivalent types from EEV (now e2v/Teledyne), Richardson Electronics, and Perkin-Elmer. Contact us with your current part number for availability and pricing.

Can you source obsolete vacuum rectifier tubes?

Yes. PartnerTubes maintains cross-reference databases for vintage and obsolete vacuum rectifier types including 5U4G, GZ34, 5Y3, 866A, and industrial high-voltage rectifier tubes. We source from quality distributors worldwide and can often find new-old-stock (NOS) or tested used types for legacy equipment.