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.
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More Specific Codes
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Alternative Classifications
This product could be classified differently depending on its characteristics or intended use.
If electronic integrated circuits
Modern amplifier ICs classified as processors/memory ICs.
If audio equipment parts
Audio amplifier assemblies classify tubes under end-use equipment.
If radio receivers
Radio transmitter/receiver tubes under Chapter 85 communication apparatus.
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Import Tips & Compliance
• Gain factor, plate voltage ratings, and filament current specs essential
• NOS (New Old Stock) certification for vintage tubes affects valuation
• Confirm vacuum tube vs. transistor under 8541 for audio amplifiers
Related Products 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.