Diodes, Triodes, Tetrodes & Pentodes

Here you'll find the exotic cousins of a typical radio tube, including computer tubes, high frequency tubes and other specialized devices. Computer tubes resemble conventional radio tubes, but have unusual transistor-like characteristics (sharp cutoff, fast response time). High frequency tubes often come in exotic metal-and-glass or metal-and ceramic envelopes.

Amperex 6076
 Amperex 6076

The Amperex 6076 is 3kW transmitting tetrode with an integral radiator, rated for high frequency operation up to 220MHz. The 6076 was later replaced by the 6076A, which substitutes the glass portions of the envelope with white ceramic.

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Amperex 4X150A & 4X150G
 Amperex 4X150A & 4X150G

The Amperex 4X150A is a UHF radial beam power tetrode with forced-air cooling, rated for 150W at 500MHz. The 4X150G is a similar radio beam tetrode with a coaxial base, rated for 500MHz CW or 1.5GHz pulsed operation. Both the 4X150A and 4X150G were once widely used in amateur radio transmitters.

Svetlana 4X150A / 7034 Datasheet (PDF)
Eimac 4X150G / 8172 Datasheet (PDF)

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Amperex EA53
 Amperex EA53

The EA53 is a high frequency rectifier, rated at up to 1 GHz. The EA53 is used as a measuring diode in the AC probe of the Hewlett-Packard 410B Vacuum Tube Voltmeter.

Philips EA53 Datasheet

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Arcturus 551
 Arcturus 551

From 1927 to 1933, Arcturus Radio Company manufactured a family of radio tubes sealed in blue glass balloon envelopes. While most of their devices were various types of triode, Arcturus was also a pioneer of both the variable mu tetrode and the pentode. Introduced in 1931, the Arcturus 551 was the first commercially available variable mu tetrode, and was later copied by numerous other manufacturers. Clones of the 551 include the RCA UY235 and the General Electric 35/51.

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Eimac 2-01C
 Eimac 2-01C

The Eimac 2-01C is a miniature radio frequency rectifier tube with a maximum operating frequency of 2.8GHz. The 2-01C was used in the AC probes of early Hewlett-Packard vacuum tube voltmeters, but was later replaced with the more rugged but less versatile Philips EA53.

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Eimac 3CX1500A7
 Eimac 3CX1500A7

The Eimac 3CX1500A7 is a large power triode intended for use as an audo or RF amplifier. The 3CX1500A7 is rated for 2075W output at 30MHz, or 1520W at up to 220MHz. Like many Eimac power tubes, the 4CX1500A7 is forced-air cooled, with a maximum anode core temperature of 250C.

Eimac 3CX1500A7 Datasheet (PDF)

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Eimac 4CX300A
 Eimac 4CX300A

The Eimac 4CX300A is a miniature power tetrode rated at 500MHz, 300W dissipation. The 4CX300A has an unusual breechlock terminal base, and requires a special Eimac X-648 socket.

Eimac 4CX300A Datasheet (PDF)

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General Electric CAA-322
 General Electric CAA-322

The CAA-322 is a metal-and-ceramic planar diode used in high frequency applications (up to 1.5 GHz).

Machlett ML-322 Datasheet

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General Electric JAN-CG-6442
 General Electric JAN-CG-6442

The 6442 is a high-mu metal-and-ceramic planar triode used in high frequency applications (up to 5 GHz). This particular example is a JAN-CG variation.

GE 6442 Datasheet

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General Electric KR-8 & KR-9
 General Electric KR-8 & KR-9

Devices included in this entry:

General Electric KR-8 rectifier
General Electric KR-9 rectifier (pictured in thumbnail)


The GE KR-8 and KR-9 Kenotron rectifiers are large, high voltage X-ray rectifiers packaged in an unusual ribbed envelope with a large metal dome extending from the anode cap. GE made a number of KR-series rectifiers in this style, but little is known about their specifications.

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General Electric JAN-CG-3C22
 General Electric JAN-CG-3C22

The 3C22 is a high power transmitter triode capable of 125W operation at 1.5GHz. The 3C22 was used in the AN/APT-5 radar jammer.

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Heintz & Kaufman 'Gammatron' 24-G / VT-204
 Heintz & Kaufman 'Gammatron' 24-G / VT-204

The Heintz & Kaufman 'Gammatron' 24G is a primitive VHF triode with top and side connectors and a four-pin base.

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ITT F-265
 ITT F-265

The ITT F-265 appears to be a fairly typical medium-sized ceramic-and-metal thyratron. Specifications are unknown.

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Machlett EE-103
 Machlett EE-103

The Machlett EE-103 appears to be a planar cermet transmitter tube. Specifications are unknown.

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Machlett 'Keleket' ML-1K
 Machlett 'Keleket' ML-1K

The Machlett 'Keleket' ML-1K is a 140kV X-ray rectifier, similar in function to the GE Kenotron KR-series rectifiers. The ML-1K is designed for oil-immersed operation.

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National Electronics NL-710 / 6011
 National Electronics NL-710 / 6011

The National Electronics NL-710 is a gas- and mercury-filled thyratron, intended for ignitor firing or as a regulated rectifier. The NL-710 has a maximum 2.5A continuous output, or a 30A instantaneous pulse. National also manufactured the NL-710L, a version with a lug-type base.

National Electronics NL-710 / 6011 Datasheet (PDF)

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National Electronics 6252
 National Electronics 6252

The National Electronics 6252 is a double tetrode in an unusual cylindrical envelope. 12.6V 0.65A filament.

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RCA 446A
 RCA 446A

The RCA 446A is an early 'lighthouse' style high frequency disc-seal planar triode with a standard octal base. The 446A is designed to operate within a coaxial cavity.

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RCA 5876A
 RCA 5876A

The 5876A is a high-mu pencil triode used in high frequency applications (up to 3 GHz). The 5876A is a component in the popular HP 608 Signal Generator.

RCA 5876A Datasheet

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RCA 6161
 RCA 6161

The RCA 6161 is a power transmitter triode with forced-air cooling and an integral radiator. The 6161 operates as a power amplifier or oscillator, up to 900MHz at full power, 2.5GHz at reduced power.

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RCA 8025
 RCA 8025

The RCA 8025 is an unusual 500MHz, 40W transmitting triode with four side contacts.

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RCA Nuvistor Series
 RCA Nuvistor Series

Devices included in this entry:

RCA 2CW4 medium mu triode
General Electric 2CW4 high mu triode
Raytheon 2DV4 medium mu triode
Zenith 2DV4 medium mu triode
Philips ECG 7587 sharp cutoff tetrode (pictured in thumbnail)


Introduced in 1959, the RCA Nuvistor is a family of subminiature, high performance vacuum tubes housed in a ceramic-and-metal envelope. Unlike conventional tubes which are evacuated after assembly, Nuvistors were assembled in a vacuum chamber by robotic equipment. Approximately a dozen different Nuvistor part numbers were produced, the base design being a medium mu triode with a 6.3V filament. A Nuvistor tetrode was also developed, as were variants with 2.1V and 12.6V filaments.

Nuvistors were a final gasp of the waning tube industry, designed to compete with newly available transistor products of the late 1950s. Though initially manufactured by RCA for use in their line of 'New Vista' color televisions, Nuvistors were also manufactured by GE, Philips and Raytheon, and were used in high performance audio and test equipment through the 1960s.

RCA Nuvistor Tubes Datasheet (PDF)

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Raytheon VT255 / JAN-CRP705A
 Raytheon VT255 / JAN-CRP705A

The VT255 is a 30kV@50ma half-wave rectifier with a 5V filament.

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Sylvania 5606
 Sylvania 5606

The Sylvania 5606 is a large 20KW triode with an unusual oversized external anode. The 5606 was used in both communication equipment and as an industrial heating element.

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Sylvania 5642
 Sylvania 5642

The Sylvania 5642 is a subminiature high voltage flyback diode used in conjunction with an oscilloscope CRT. The 5642 is rated for 10kV at 0.25mA.

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Telefunken RV12P2000
 Telefunken RV12P2000

The Telefunken RV12P2000 pentode was the most common vacuum tube manufactured by Nazi Germany. Rated at 580mW output, the RV12P2000 was intended as a high frequency amplifier, but was also implemented as an oscillator, IF amplifier and audio amplifier. The RV12P2000 has an unusual 6-pin radial base, and is mounted inversely in its custom socket.

The RV12P2000 remained popular after the end of World War II. The example pictured here was manufactured around 1947.

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Tung-Sol 5678
 Tung-Sol 5678

Devices included in this entry:

Tung-Sol JAN-5678 subminiature pentode
Sonotone JOZ-5678 subminiature pentode
Tung-Sol JTL-5678 subminiature pentode (pictured in thumbnail)


The Tung-Sol 5678 is a subminiature high frequency pentode with an integral metallic shield.

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Western Electric 416B
 Western Electric 416B

The Western Electric 416B is a high frequency planar triode, used in the Northern Electric TD-2 point-to-point microwave radio system. The 416B is rated for 0.5W output at 4GHz.

Western Electric 416B Datasheet (PDF)

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Western Electric 418A
 Western Electric 418A

The Western Electric 418A is a power triode with an indirectly heated cathode. The 418A was designed for use as a power output tube in broadband video and intermediate-frequency amplifiers.

Western Electric 418A Datasheet (PDF)

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