RF Power Grid Tubes · Tetrodes
4CX250B Ceramic Tetrode
Available on request
Eimac / CPI
4CX250B
Classic ceramic-metal beam tetrode with 250 W plate dissipation, widely used in HF and VHF amplifiers up to 110 MHz.
- Plate Dissipation
- 250 W
- Max Frequency
- 110 MHz
- Max Plate Voltage
- 3.5 kV
- Max Plate Current
- 175 mA
Worldwide shipping
Cross-reference support
Grunius BV · Groningen, NL
4CX250B
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About the 4CX250B
The 4CX250B is a power tetrode manufactured by Eimac / CPI. Classic ceramic-metal beam tetrode with 250 W plate dissipation, widely used in HF and VHF amplifiers up to 110 MHz.
Key ratings of the 4CX250B include tube type Beam Tetrode, plate dissipation 250 W, max plate voltage 3.5 kV, max plate current 175 mA, screen voltage 300 V and transconductance 25 mA/V.
Typical applications are HF linear amplifiers, VHF broadcast transmitters, industrial RF heating, amateur radio amplifiers and military HF communications. Notable features: industry-standard 250 W ceramic tetrode, proven 60-year design heritage, 110 MHz max frequency and water-cooled anode option.
Power tetrodes add a screen grid to the triode structure, giving higher gain and lower drive power. They are widely used in FM and TV broadcast transmitters, HF communications, plasma heating and accelerator RF systems, usually together with vacuum capacitors in the output network.
PartnerTubes supplies the 4CX250B worldwide from Groningen, the Netherlands — availability, lead time and price are confirmed per enquiry. Our team can help with equivalent and cross-reference types, sockets and accessories, and supply programmes for OEM and maintenance customers. Interchangeability must always be confirmed for the specific equipment.
Technical specifications
| Tube Type | Beam Tetrode |
|---|---|
| Plate Dissipation | 250 W |
| Max Plate Voltage | 3.5 kV |
| Max Plate Current | 175 mA |
| Screen Voltage | 300 V |
| Transconductance | 25 mA/V |
| Max Frequency | 110 MHz |
| Filament Voltage | 6.0 V |
| Filament Current | 2.5 A |
| Envelope | Ceramic-metal |
Specifications are indicative and based on published manufacturer data. Always verify against the official datasheet and confirm suitability for your application before ordering.
Applications & features
Used in
- HF linear amplifiers
- VHF broadcast transmitters
- Industrial RF heating
- Amateur radio amplifiers
- Military HF communications
Key features
- Industry-standard 250 W ceramic tetrode
- Proven 60-year design heritage
- 110 MHz max frequency
- Water-cooled anode option
- Socket-compatible with 4CX250R
Related parts & equivalents
Recommended alongside or as alternatives to the 4CX250B.
Similar RF Power Grid Tubes
Comparable type, ratings, manufacturer or applications.
Vacuum capacitors for output networks
Often ordered with the 4CX250B for the same system.
Jennings UCSL 15–100 pF Variable Vacuum Capacitor 20 kV
Jennings Technology (CPI)
Capacitance Range 15–100 pF
Jennings UCSL 25–200 pF Variable Vacuum Capacitor 25 kV
Jennings Technology (CPI)
Capacitance Range 25–200 pF
Jennings UCSL 10–60 pF Variable Vacuum Capacitor
Jennings Technology (CPI)
Capacitance Range 10–60 pF
Frequently asked questions
What is the 4CX250B?
The 4CX250B is a power tetrode manufactured by Eimac / CPI. Classic ceramic-metal beam tetrode with 250 W plate dissipation, widely used in HF and VHF amplifiers up to 110 MHz.
What are the specifications of the 4CX250B?
Tube Type: Beam Tetrode; Plate Dissipation: 250 W; Max Plate Voltage: 3.5 kV; Max Plate Current: 175 mA; Screen Voltage: 300 V; Transconductance: 25 mA/V; Max Frequency: 110 MHz; Filament Voltage: 6.0 V; Filament Current: 2.5 A; Envelope: Ceramic-metal.
What is the 4CX250B used for?
The 4CX250B is used in HF linear amplifiers, VHF broadcast transmitters, industrial RF heating, amateur radio amplifiers and military HF communications.
What are alternatives or related parts to the 4CX250B?
Related and comparable parts include 4CX250R, 4CX1000A, 4-125A, 4CX350A, 4CX10000D and 4CX3000A. Contact PartnerTubes to confirm interchangeability for your equipment.
Where can I buy the 4CX250B?
The 4CX250B is available from PartnerTubes (Grunius BV, Groningen, Netherlands) with worldwide shipping. Availability and lead time are confirmed on request. Request a quote at https://www.partnertubes.com/contact/?part=4CX250B or email info@partnertubes.com.