Other
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
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]
Subheadings
Products classified under HTS 8540.89.00
Magnetron Injection-Locked Tube
Phase-locked magnetron tubes for coherent microwave power combining in radar systems. Classified under HTS 8540.89.00 as specialized thermionic tubes with injection locking circuitry for phase control.
Klystron Power Amplifier Tube
Klystron tubes are specialized linear beam vacuum tubes used for amplification of microwave signals in high-power applications like radio transmitters and particle accelerators. Classified under HTS 8540.89.00 as other thermionic tubes due to their electron beam focusing mechanism in vacuum environment.
Xenon Flashtube Trigger Tube
High-voltage gas tubes triggering xenon flashtubes in high-intensity strobe lighting. HTS 8540.89.00 covers these as other gas-filled tubes initiating capacitive discharge through gas ionization.
Thyratron Gas-Filled Switching Tube
Thyratrons are gas-filled tubes containing low-pressure inert gas used for high-power switching and rectification in industrial applications. They qualify under HTS 8540.89.00 as other gas-filled tubes functioning through gas ionization triggered by cathode emission.
Ignitron Mercury Arc Rectifier Tube
Ignitrons are large mercury arc rectifier tubes used for high-current DC power conversion in industrial applications like aluminum smelting. HTS 8540.89.00 includes these mercury vapor-filled tubes operating via cathode-initiated arc discharge.
Photomultiplier Tube (PMT)
Photomultiplier tubes convert weak light signals into electrical pulses through electron multiplication across multiple dynodes. Classified under HTS 8540.89.00 as photocathode tubes designed for photon detection in scientific instruments.
Hydrogen Thyratron Pulse Modulator Tube
High-speed hydrogen thyratrons designed for pulse power applications in radar and particle physics, offering fast recovery times. HTS 8540.89.00 covers these gas-filled tubes optimized for repetitive high-voltage switching.
Deuterium Arc Lamp Electrode Tube
Specialized gas discharge tubes using deuterium gas for continuous UV spectrum generation in spectroscopy. Falls under HTS 8540.89.00 as gas-filled tubes producing light through cathode-initiated arc discharge.
Cold Cathode Ion Gauge Tube
Cold cathode tubes measuring ultra-high vacuum by ionizing residual gas with high-voltage discharge between electrodes. HTS 8540.89.00 includes these as other cold cathode tubes for vacuum measurement applications.
Trigger Tube for Strobe Systems
Gas-filled trigger tubes initiate high-voltage discharge in strobe/flash systems through controlled gas ionization. Classified under HTS 8540.89.00 as other gas-filled tubes designed for switching high-power lighting circuits.
Grid-Controlled Vacuum Tube
Triode vacuum tubes with control grid for amplification in audio and RF applications. HTS 8540.89.00 covers these thermionic tubes where grid modulates electron flow from cathode to anode.
Radiation Counter Geiger-Müller Tube
Gas-filled tubes detecting ionizing radiation through avalanche multiplication of electrons in detection gas. Classified under HTS 8540.89.00 as other gas-filled tubes specifically for radiation measurement.
Microwave Backward Wave Oscillator Tube
Backward wave oscillator tubes generate tunable microwave signals for test equipment and radar. HTS 8540.89.00 includes these velocity-modulated tubes producing electromagnetic waves through backward wave interaction.
Magnetron Oscillator Tube
A magnetron tube is a high-power vacuum tube that generates microwave frequencies using the interaction of a stream of electrons from a heated cathode and a powerful magnetic field. It falls under HTS 8540.89.00 as an other thermionic tube, specifically a cold cathode or vacuum tube used primarily in microwave ovens and radar systems.
Traveling Wave Tube (TWT)
Traveling wave tubes are velocity-modulated tubes that provide high gain amplification at microwave frequencies, essential for satellite communications and military radar. HTS 8540.89.00 covers these as other thermionic tubes due to their specialized electron interaction with electromagnetic waves.