Compactron
Compactrons are a type of vacuum tube, which contain multiple electrode structures packed into a single enclosure. They were designed to compete with early transistor electronics and were used in televisions, radios, and similar roles.
History
The Compactron was a trade name applied to multi-electrode structure tubes specifically constructed on a 12-pin Duodecar base. This
Use was prevalent in televisions because transistors were slow to achieve the high power and frequency capabilities needed particularly in color television sets. The first portable color television, the General Electric Porta-Color, was designed using 13 tubes, 10 of which were Compactrons. Even before the compactron design was unveiled, nearly all tube based electronic equipment used multi-electrode tubes of one type or another. Virtually every AM/FM radio receiver of the 1950s and 60's used a 6AK8 (EABC80) tube (or equivalent) consisting of three diodes and a triode which was designed in 1954.[4]
Compactron's integrated valve design helped lower power consumption and heat generation (they were to tubes what
Notable features
A distinguishing feature of most Compactrons is the placement of the evacuation tip on the bottom end, rather than the top end as was customary with "miniature" tubes, and a characteristic 3/4" diameter circle pin pattern.
- Most Compactrons ranged in glass envelope diameter from 28 to 70 mm depending upon the internal configuration. Variations of the Compactron design were made by Sylvania and by some Japanese firms.
Examples
Examples of Compactrons type types include:
- 6AG11 double diode similar to 6AL5, double triode high-mu similar to 12AT7. Designed for FM stereo multiplex service.
- 6BK11 triple triode. Two of the triodes are similar to 12AX7 and one of them is similar to 5751.
- 6C10 high-mu triple triode, all three being similar to Edison Swan (later Mazda)6C10 triode-hexode
- 6M11 twin triode - pentode. Designed for sync separators and AGC amplifier circuits.
- 6K11 triple triode. Designed for sync separators and AGC amplifier circuits.
- 6LF6 beam power pentode with anode cap. Designed for horizontal output service.
- 8B10 twin triode - twin diode. Designed for horizontal phase detector service, and horizontal oscillator service.
- 12AE10 twin pentode. Designed for FM discriminator/detector, and audio output.
- 38HK7 pentode diode. Designed for horizontal output service and as a damper diode
- 1AD2 diode high voltage, used in flyback transformer rectification
Due to their specific applications in television circuits, many different Compactron types were produced. Almost all were assigned using standard US tube numbers.
Technological obsolescence
This section possibly contains original research. (July 2016) |
Integrated circuits (of the analogue and digital type) gradually took over all of the functions that the Compactron was designed for. "Hybrid" television sets produced in the early to mid-1970s made use of a combination of tubes (typically Compactrons), transistors, and integrated circuits in the same set.[5] By the mid-1980s this type of tube was functionally obsolete. Compactrons simply don't exist in any TV sets designed after 1986. Other specialist uses of the tube declined in parallel with the television set manufacture. Manufacture of Compactrons ceased in the early 1990s. New old stock replacements for almost all Compactron types produced are easily found for sale on the Internet.[2]
References
Notes
- ^ "Multi-Function Compactrons Promise Two-Tube Radio". Electronic Design. July 20, 1960. p. 74. Retrieved 2009-11-03.
- ^ a b c Duntemann, Jeff (2008). "Compactron Tubes: A Junkbox Guide". Copperwood Media LLC. Retrieved 2009-11-03.
- ^ "3NF, Tube 3NF; Röhre 3NF ID1195, MULTI-SYSTEM, internal coup".
- ^ "EABC80 @ The Valve Museum".
- ^ Eng, John. "Televisions 1946-1999". Retrieved May 2, 2021.