Compactrons are electronic vacuum tube units which contain arrangements of diode

Diode

In electronics, a diode is a type of two-terminal electronic component with a nonlinear current–voltage characteristic. A semiconductor diode, the most common type today, is a crystalline piece of semiconductor material connected to two electrical terminals...

s, triode

Triode

A triode is an electronic amplification device having three active electrodes. The term most commonly applies to a vacuum tube with three elements: the filament or cathode, the grid, and the plate or anode. The triode vacuum tube was the first electronic amplification device...

s, or pentode

Pentode

A pentode is an electronic device having five active electrodes. The term most commonly applies to a three-grid vacuum tube , which was invented by the Dutchman Bernhard D.H. Tellegen in 1926...

s in multiple combination arrays, as well as high or low-voltage

Voltage

Voltage, otherwise known as electrical potential difference or electric tension is the difference in electric potential between two points — or the difference in electric potential energy per unit charge between two points...

 and power types.

History

The Compactron is a 12-pin vacuum tube

Vacuum tube

In electronics, a vacuum tube, electron tube , or thermionic valve , reduced to simply "tube" or "valve" in everyday parlance, is a device that relies on the flow of electric current through a vacuum...

 family introduced in 1961 by General Electric

General Electric

General Electric Company , or GE, is an American multinational conglomerate corporation incorporated in Schenectady, New York and headquartered in Fairfield, Connecticut, United States...

 in Owensboro, Kentucky

Owensboro, Kentucky

Owensboro is the fourth largest city by population in the U.S. state of Kentucky. It is the county seat of Daviess County. It is located on U.S. Route 60 about southeast of Evansville, Indiana, and is the principal city of the Owensboro, Kentucky, Metropolitan Statistical Area. The city's...

  to compete with transistorized electronics during the solid state

Solid state (electronics)

Solid-state electronics are those circuits or devices built entirely from solid materials and in which the electrons, or other charge carriers, are confined entirely within the solid material...

 transition. Television

Television

Television is a telecommunication medium for transmitting and receiving moving images that can be monochrome or colored, with accompanying sound...

 sets were a primary application.

Use was prevalent in televisions because transistors were slow to achieve the high power and frequency capabilities needed particularly in color television sets.

Compactron's integrated valve design helped lower power consumption and heat generation (they were to tubes what integrated circuits were to transistors). Compactrons were also used in a few high end Hi-Fi stereos. No modern tube based Hi-Fi systems are known to use this tube type, as simpler and more readily available tubes have again filled this niche.

Notable features

A distinguishing feature of most Compactrons is the placement of the evacuation tip

Evacuation tip

The evacuation tip is a port on a nixie or vacuum tube used to evacuate gases from the tube, and in the case of nixies, add the proper mix of gases before being sealed. It provides a convenient port for the amateur glasshacker to introduce gases to alter the performance of the tube. It is also...

 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 1 1/8" to 2 3/4" depending upon the internal configuration. Variations of the Compactron design were made by Sylvania
  Osram Sylvania
  Osram Sylvania Inc. is the North American operation of lighting manufacturer Osram GmbH, which is owned by Siemens AG. It was established in January 1993, with the acquisition of GTE’s Sylvania lighting division by Osram GmbH....
  
  and by some Japanese firms.

Design variations

These types of compactron are known:

• 6AG11 high-mu twin triode
• 6M11 twin triode - pentode
• 12AE10 twin pentode
• 8B10 twin triode - twin diode
• 38HK7 pentode diode
• 6K11 triple triode
• 6LF6 beam power tetrode with anode cap

Technological obsolescence

Integrated circuits (of the analogue and digital type) gradually took over all of the functions that the compactron was designed for. 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. Finding replacement parts is very difficult if not impossible, as this component was never standardized.