Gas and vapor electron tubes
Thermionic, cold cathode or photocathode tubes (for example, vacuum or vapor or gas filled tubes, mercury arc rectifying tubes, cathode-ray tubes, television camera tubes); parts thereof: > Other tubes: > Other > Gas and vapor electron tubes
Duty Rate (from China)
Except for products described in headings 9903.03.02–9903.03.11, articles the product of any country, as provided for in subdivision (aa) of U.S. note 2 to this subchapter
Except as provided in headings 9903.88.05, 9903.88.06, 9903.88.07, 9903.88.08, 9903.88.10, 9903.88.11, 9903.88.14, 9903.88.19, 9903.88.50, 9903.88.52, 9903.88.58, 9903.88.60, 9903.88.62, 9903.88.66, 9903.88.67, 9903.88.68, or 9903.88.69, articles the product of China, as provided for in U.S. note 20(a) to this subchapter and as provided for in the subheadings enumerated in U.S. note 20(b) [to this subchapter]
Products classified under HTS 8540.89.00.20
Thyratron Gas-Filled Switching Tube
A thyratron is a gas-filled electron tube used for high-power switching applications in industrial controls and pulsed power systems. It operates by ionizing gas between electrodes to conduct current, fitting under HTS 8540.89.0020 as a gas electron tube distinct from vacuum or photocathode types.
Hydrogen Thyratron Pulse Modulator Tube
Hydrogen thyratrons are specialized gas electron tubes designed for radar pulse modulators and high-voltage switching in scientific instruments. The low-pressure hydrogen gas enables fast switching, qualifying as a vapor electron tube under HTS 8540.89.0020.
Mercury Arc Rectifier Gas Tube
Mercury arc rectifier tubes convert AC to DC using ionized mercury vapor in a vacuum envelope, historically used in industrial power supplies. Though largely obsolete, they remain classified as gas-filled electron tubes under HTS 8540.89.0020.
Deuterium Stabilized Gas Laser Tube
Deuterium gas laser tubes provide stable UV output for spectroscopy using gas discharge excitation. The sealed tube contains deuterium at low pressure, classifying as a gas electron tube under HTS 8540.89.0020 despite laser application.
Argon Ion Gas Laser Tube
Argon ion laser tubes generate blue-green laser light through electrical discharge in argon gas, used in scientific research and holography. Classified as gas-filled electron tubes under HTS 8540.89.0020 based on tube construction.
Ignitron Mercury Pool Tube
Ignitrons are high-current mercury pool gas tubes for welding control and electrolytic processes, igniting mercury vapor arc for conduction. They qualify under HTS 8540.89.0020 as vapor electron tubes.
Magnetron Gas-Filled Amplifier Tube
Gas-filled magnetron tubes amplify microwave signals using crossed-field electron interaction in low-pressure gas. Used in radar amplifiers, they classify as gas electron tubes under HTS 8540.89.0020.
Klystron Gas-Loaded Reflex Tube
Gas-loaded klystron tubes use controlled gas pressure for microwave power generation in scientific accelerators. The gas affects electron velocity, qualifying as vapor electron tubes under HTS 8540.89.0020.
Geiger-Mueller Counter Tube
Geiger-Mueller tubes detect ionizing radiation through gas ionization avalanche in a cylindrical gas volume. Essential for radiation monitoring, they classify as gas electron tubes under HTS 8540.89.0020.
Proportional Counter Gas Tube
Proportional counters use gas multiplication for precise radiation spectroscopy in nuclear physics. The gas amplification region creates proportional charge pulses, fitting HTS 8540.89.0020 as gas electron tubes.
Xenon Flashtube Trigger Gas Tube
Xenon flashtube trigger tubes initiate high-power photographic flashes using gas spark discharge. The high-voltage gas breakdown provides reliable triggering, classifying under HTS 8540.89.0020.
Helium-Neon Laser Plasma Tube
HeNe laser plasma tubes generate visible laser light through gas discharge excitation of helium-neon mixture. Used in alignment and metrology, they qualify as gas electron tubes under HTS 8540.89.0020.
Spark Gap Gas Switch Tube
Pressurized gas spark gap tubes provide fast high-voltage switching for pulse power systems and lightning protection. The controlled gas breakdown voltage enables precise switching, under HTS 8540.89.0020.
CO2 Laser Gas Discharge Tube
CO2 laser tubes use high-pressure CO2-N2-He gas mixture for 10.6μm infrared laser output in material processing. The RF or DC excited gas discharge classifies as vapor electron tube under HTS 8540.89.0020.
Neon Glow Transfer Tube
Neon glow transfer tubes use low-pressure neon gas for counting circuits in radiation detectors and logic applications. The gas discharge creates visible glow states for switching, fitting HTS 8540.89.0020 as vapor electron tubes.