This is a list of digital computers using discrete transistor

Transistor

A transistor is a semiconductor device used to amplify and switch electronic signals and power. It is composed of a semiconductor material with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current...

s as their primary logic elements. Transistors were a feature of logic design for computers from about 1960, when reliable transistors became economically available, until hybrid and monolithic integrated circuit

Integrated circuit

An integrated circuit or monolithic integrated circuit is an electronic circuit manufactured by the patterned diffusion of trace elements into the surface of a thin substrate of semiconductor material...

s displaced them in the 1970s. The list is organized by operational date or delivery year to customers. Computers announced, but never completed, are not included. Note that some very early "transistor" computers may still have included vacuum tubes in the power supply or for auxiliary functions.

1953

• University of Manchester
  University of Manchester
  The University of Manchester is a public research university located in Manchester, United Kingdom. It is a "red brick" university and a member of the Russell Group of research-intensive British universities and the N8 Group...
  
   Transistor computer
  Transistor computer
  A transistor computer is a computer which uses discrete transistors instead of vacuum tubes. The "first generation" of electronic computers used vacuum tubes, which generated large amounts of heat, were bulky, and were unreliable. A "second generation" of computers, through the late 1950s and...
  
   1953 (prototype) 1955 (full scale) experimental

1954

• Bell Labs TRADIC
  TRADIC
  The TRADIC was the first transistorized computer in the USA, completed in 1954....
  
    for U.S. Air Force
• IBM 608
  IBM 608
  The IBM 608 was the first IBM product to use transistor circuits without any vacuum tubes and is believed to be the world's first all-transistorized calculator to be manufactured for the commercial market.Pugh, Emerson W.; Johnson, Lyle R.; Palmer, John H.; . IBM's 360 and early 370 systems. MIT...
  
   transistor calculator, demonstrated October 1954, announced 1955, first shipped Dec 1957

1955

• Harwell CADET
  Harwell CADET
  The Harwell CADET was the first fully transistorised computer in Europe, and may have been the first fully transistorised computer in the world....
  
   demonstrated February 1955, one off scientific computer
• Mailüfterl
  Mailüfterl
  Mailüfterl is an Austrian nickname for the first transistorized computer on the European mainland. The first computers of this kind were TRADIC, Harwell CADET and TX-0.It was built in 1955 at the Vienna University of Technology by Heinz Zemanek...
  
   experimental

1956

• MIT TX-0
  TX-0
  The TX-0, for Transistorized Experimental computer zero, but affectionately referred to as tixo , was an early fully transistorized computer and contained a then-huge 64K of 18-bit words of magnetic core memory. The TX-0 was built in 1955 and went online in 1956 and was used continually through the...
  
  
• Electrotechnical Laboratory ETL Mark III (Japan) experimental
• Metrovick 950
  Metrovick 950
  The Metrovick 950 was a transistorized computer, built from 1956 onwards by British company Metropolitan-Vickers, to the extent of six or seven machines, which were "used commercially within the company" or "mainly for internal use"...
  
  

1957

• Burroughs
  Burroughs
  The Burroughs Corporation was a major American manufacturer of business equipment. The company was founded in 1886 as the American Arithmometer Company and was assimilated in the 1986 merger that resulted in the creation of Unisys. The company's history paralleled many of the major developments in...
  
   SM-65 Atlas ICBM Guidance Computer MOD1, AN/GSQ-33 (no relation to Manchester ATLAS)
• NCR 304
  NCR 304
  The NCR 304, introduced in 1957, was National Cash Register 's first transistor-based computer. The 304 was developed and manufactured in cooperation with General Electric.Its follow-on was the NCR 315....
  
  
• Philco
  Philco
  Philco, the Philadelphia Storage Battery Company , was a pioneer in early battery, radio, and television production as well as former employer of Philo Farnsworth, inventor of cathode ray tube television...
  
   Transac S-1000 - Navy/NSA SOLO, one-off for NSA
• Univac
  UNIVAC
  UNIVAC is the name of a business unit and division of the Remington Rand company formed by the 1950 purchase of the Eckert-Mauchly Computer Corporation, founded four years earlier by ENIAC inventors J. Presper Eckert and John Mauchly, and the associated line of computers which continues to this day...
  
   TRANSTEC, for US Navy
• Univac
  UNIVAC
  UNIVAC is the name of a business unit and division of the Remington Rand company formed by the 1950 purchase of the Eckert-Mauchly Computer Corporation, founded four years earlier by ENIAC inventors J. Presper Eckert and John Mauchly, and the associated line of computers which continues to this day...
  
   ATHENA, US Air Force missile guidance (ground control)

1958

• Electrologica X1
  Electrologica X1
  The Electrologica X1 was a digital computer designed and manufactured in the Netherlands from 1958 to 1965. About thirty were produced and sold in the Netherlands and abroad....
  
  
• TX-2
  TX-2
  The MIT Lincoln Laboratory TX-2 computer was the successor to the Lincoln TX-0 and was known for its role in advancing both artificial intelligence and human-computer interaction.- Specifications :...
  
  
• UNIVAC Solid State
  UNIVAC Solid State
  The UNIVAC Solid State was a 2-address, bi-quinary coded decimal computer, with memory on a rotating drum with 5000 signed 10 digit words, spinning at 17,667 RPM in a helium atmosphere. It was announced by Sperry Rand in December 1958, as a response to the IBM 650...
  
   ("mostly" solid state)
• Ferranti Argus
  Ferranti Argus
  Ferranti's Argus computers were a line of industrial control computers offered from the 1960s into the 1980s. They were widely used in a variety of roles in Europe, particularly in the UK where they continue to serve as monitoring and control systems for nuclear reactors.-Original series:The...
  
  
• RCA 501 intended as a commercial system but used in military applications

1959

• Olivetti Elea
  Olivetti Elea
  The Elea 9003 is one of a series of mainframe computers Olivetti developed starting in the late 1950s. The system, made entirely with transistors for high performance, was conceived, designed and developed by a small group of researchers led by Mario Tchou...
  
   9003
• MOBIDIC
• IBM 7090
  IBM 7090
  The IBM 7090 was a second-generation transistorized version of the earlier IBM 709 vacuum tube mainframe computers and was designed for "large-scale scientific and technological applications". The 7090 was the third member of the IBM 700/7000 series scientific computers. The first 7090 installation...
  
  
• IBM 1401
  IBM 1401
  The IBM 1401 was a variable wordlength decimal computer that was announced by IBM on October 5, 1959. The first member of the highly successful IBM 1400 series, it was aimed at replacing electromechanical unit record equipment for processing data stored on punched cards...
  
  
• IBM 1620 Model I
  IBM 1620 Model I
  The IBM 1620 Model I was the original implementation of the IBM 1620 scientific computer, introduced in 1959.This unit was produced as inexpensively as IBM could make it, in order to keep the price low...
  
   and successors IBM 1620 Model II
  IBM 1620 Model II
  The IBM 1620 Model II was a vastly improved implementation, compared to the original Model I, of the IBM 1620 scientific computer architecture....
  
  
• NEAC 2201 (NEC
  NEC
  , a Japanese multinational IT company, has its headquarters in Minato, Tokyo, Japan. NEC, part of the Sumitomo Group, provides information technology and network solutions to business enterprises, communications services providers and government....
  
  )
• EMIDEC 1100
  EMIDEC 1100
  -External links:**...
  
  
• TRW RW-300

1960

• Honeywell 200
  Honeywell 200
  The Honeywell 200 was a character-oriented two-address commercial computer introduced by Honeywell in the early 1960s, the basis of later models including 1200, 1250, 2200, 3200, 4200 and the later 2070, and the character processor of the Honeywell 8200....
  
  
• UNIVAC LARC
• CDC 1604
  CDC 1604
  The CDC 1604 was a 48-bit computer designed and manufactured by Seymour Cray and his team at the Control Data Corporation. The 1604 is known as the first commercially successful transistorized computer. Legend has it that the 1604 designation was chosen by adding CDC's first street address to...
  
  
• CDC 160A
  CDC 160A
  The CDC 160 and CDC 160-A were 12-bit minicomputers built by Control Data Corporation from 1960 to 1965. The 160 was designed by Seymour Cray - reportedly over a long three-day weekend...
  
  
• Datasaab D2
  Datasaab D2
  thumb|right|200px|Datasaab D2 computer at IT-ceumthumb|right|200px|Front panelD2 was a concept and prototype computer designed by Datasaab in Linköping, Sweden. It was built with discrete transistors and completed in 1960...
  
  
• DRTE Computer
  DRTE Computer
  The DRTE Computer was a transistorized computer built at the Defence Research Telecommunications Establishment , part of the Canadian Defence Research Board. It was one of the earlier fully transistorized machines, running in prototype form in 1957, and fully developed form in 1960...
  
    experimental
• Elliott 803
  Elliott 803
  The Elliott 803 was a small, medium speed digital computer manufactured by the British company Elliott Brothers in the 1960s. About 250 were built and most British universities and colleges bought one.-History:...
  
  
• AN/FSQ-32
  AN/FSQ-32
  The AN/FSQ-32 was a computer made by IBM in 1960 and 1961 for the United States Air Force Strategic Air Command . IBM called it the 4020 Military Computer, but it was more commonly known as the Q-32. Only one unit was ever built.-History:The Q-32 was installed at System Development Corporation ...
  
   (IBM 4020)
• AN/FSQ-31V
  AN/FSQ-31V
  The AN/FSQ-31V was a computer made by IBM in 1960 and 1961 for the United States Air Force Strategic Air Command . The IBM Model name for the machine was the 4020.Three Q-31 units were built...
  
  
• IBM 7070
  IBM 7070
  IBM 7070 was a decimal architecture intermediate data processing system that was introduced by IBM in June 1960. It was part of the IBM 700/7000 series, and was based on discrete transistors rather than the vacuum tubes of the 1950s. It was the company's first transistorized stored-program...
  
  
• Siemens
  Siemens
  Siemens may refer toSiemens, a German family name carried by generations of telecommunications industrialists, including:* Werner von Siemens , inventor, founder of Siemens AG...
  
   System 2002
• University of Tokyo KDO-1
• Japan Electrotechnical Laboratory ETL Mark 5,
• Mitsubishi
  Mitsubishi
  The Mitsubishi Group , Mitsubishi Group of Companies, or Mitsubishi Companies is a Japanese multinational conglomerate company that consists of a range of autonomous businesses which share the Mitsubishi brand, trademark and legacy...
  
   MELCOM 3409

1961

• Plessey
  Plessey
  The Plessey Company plc was a British-based international electronics, defence and telecommunications company. It originated in 1917, growing and diversifying into electronics. It expanded after the second world war by acquisition of companies and formed overseas companies...
  
   xL4
• MANIAC III
  MANIAC III
  The Maniac III was a second-generation electronic computer , built in 1961 for use at the Institute for Computer Research at the University of Chicago.It was designed by Nicholas Metropolis and constructed by the staff of the Institute for Computer...
  
  
• CAB500
  CAB500
  The CAB500 was a French transistor-based drum computer, designed at SEA around 1957It had an incremental compiler for a language, PAF similar to Fortran, designed by Dimitri Starynkevitch in 1957-1959. CAB 500's first model was delivered in February, 1961 , and more than a hundred examples were...
  
  
• LEO III
• English Electric KDP10
• Bendix G-20
  Bendix G-20
  The Bendix G-20 computer was introduced in 1961 by the Bendix Corporation, Computer Division, Los Angeles, California. The G-20 followed the highly successful G-15 vacuum tube computer...
  
  
• NEC
  NEC
  , a Japanese multinational IT company, has its headquarters in Minato, Tokyo, Japan. NEC, part of the Sumitomo Group, provides information technology and network solutions to business enterprises, communications services providers and government....
  
   NEAC 2205
• Fujitsu
  Fujitsu
  is a Japanese multinational information technology equipment and services company headquartered in Tokyo, Japan. It is the world's third-largest IT services provider measured by revenues....
  
   FACOM 222
• IBM 7030 Stretch
• Zuse Z23
• IBM 7080
  IBM 7080
  The IBM 7080 was a variable word length BCD transistor computer in the IBM 700/7000 series commercial architecture line, introduced in August 1961, that provided an upgrade path from the vacuum tube IBM 705 computer....
  
  
• IBM 1710
  IBM 1710
  The IBM 1710 was a process control system that IBM introduced in March 1961. It used either a 1620 I or a 1620 II Computer and specialized I/O devices .The IBM 1620 used in the 1710 system was modified in several ways, the most obvious was the addition of a very...
  
  
• Packard Bell
  Packard Bell
  Packard Bell is a Dutch computer manufacturer and a subsidiary of Acer. The name was previously used by Packard Bell, an American radio manufacturer founded in 1926. In 1986, Israeli investors bought the name for a newly formed personal computer manufacturer. Originally the company produced...
  
   250 (no relation to the modern brand of personal computer
  Personal computer
  A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...
  
  s, controller for hybrid digital/analog system)
• Matsushita
  Matsushita
  Matsushita is a Japanese place name and surname which means "below the pine tree" and may refer to:-Companies:*Matsushita Electric Industrial, now Panasonic Corporation, a multinational electronics corporation based in Kadoma, Japan...
  
   MADIC IIA
• TRW
  TRW
  TRW Inc. was an American corporation involved in a variety of businesses, mainly aerospace, automotive, and credit reporting. It was a pioneer in multiple fields including electronic components, integrated circuits, computers, software and systems engineering. TRW built many spacecraft,...
  
  -130 aka AN/UYK-1 for Transit
  Transit (satellite)
  The TRANSIT system, also known as NAVSAT , was the first satellite navigation system to be used operationally. The system was primarily used by the U.S...
  
   submarine navigation satellite receivers

1962

• Philco
  Philco
  Philco, the Philadelphia Storage Battery Company , was a pioneer in early battery, radio, and television production as well as former employer of Philo Farnsworth, inventor of cathode ray tube television...
  
   212
• Atlas Computer (Manchester)
  Atlas Computer (Manchester)
  The Atlas Computer was a joint development between the University of Manchester, Ferranti, and Plessey. The first Atlas, installed at Manchester University and officially commissioned in 1962, was one of the world's first supercomputers, considered to be the most powerful computer in the world at...
  
  
• ASC-15
  ASC-15
  The ASC-15 was a digital computer developed by International Business Machines for use on the Titan II intercontinental ballistic missile . It was subsequently modified and used on the Titan III and Saturn I Block II launch vehicles. Its principal function on these rockets was to make navigation...
  
  
• ICT 1301
  ICT 1301
  The ICT 1301 and its smaller derivative ICT 1300 were early business computers from International Computers and Tabulators. Typical of mid-sized machines of the era they used core memory, drum storage and punched cards, but they were unusual in that they were based on decimal logic instead of...
  
  
• ILLIAC II
  ILLIAC II
  The ILLIAC II was a revolutionary super-computer built by the University of Illinois that became operational in 1962.-Description:The concept, proposed in 1958, pioneered Emitter-coupled logic circuitry, pipelining, and transistor memory with a design goal of 100x speedup compared to ILLIAC...
  
  
• UNIVAC 1107
  UNIVAC 1107
  The UNIVAC 1107 was the first member of Sperry Rand's UNIVAC 1100 series of computers, introduced in October 1962. It was also known as the Thin Film Computer because of its use of thin film memory for its register storage...
  
  
• UMC 10
  UMC (Computer)
  UMC is a family of computers produced by Elwro from 1962....
  
  
• IBM 7094
  IBM 7090
  The IBM 7090 was a second-generation transistorized version of the earlier IBM 709 vacuum tube mainframe computers and was designed for "large-scale scientific and technological applications". The 7090 was the third member of the IBM 700/7000 series scientific computers. The first 7090 installation...
  
  
• Autonetics D-17B
  D-17B
  The D-17B is a computer used in missile guidance systems, specifically the Minuteman I NS-1OQ missile guidance system, which contains a D-17B computer, the associated stable platform, and power supplies. The D-17B weighs approximately , contains 1,521 transistors, 6,282 diodes, 1,116 capacitors,...
  
  
• Regnecentralen
  Regnecentralen
  Regnecentralen, or RC for short, was the first Danish computer company, founded on October 12, 1955. Through the 1950s and 60s they designed a series of computers, originally for their own use, and later to be sold commercially. Descendants of these systems sold well into the 1980s...
  
   GIER
• RW-400 aka AN/FSQ-27 by TRW
  TRW
  TRW Inc. was an American corporation involved in a variety of businesses, mainly aerospace, automotive, and credit reporting. It was a pioneer in multiple fields including electronic components, integrated circuits, computers, software and systems engineering. TRW built many spacecraft,...
  
  

1963

• Librascope
  Librascope
  Librascope was a Glendale, California division of General Precision Inc. founded in 1937 by Lewis W. Imm to improve aircraft load balancing, and acquired by General Precision in 1941....
  
   LGP-21
• IBM 7040
  IBM 7040
  The IBM 7040 was a historic but short-lived model of transistor computer built in the 1960s.It was announced by IBM in December 1961, but did not ship until April, 1963. A later member of the IBM 700/7000 series of scientific computers, it was a scaled down version of the IBM 7090. It was not fully...
  
   and IBM 7044
• CDC 3000
  CDC 3000
  The CDC 3000 series computers from Control Data Corporation were mid-1960s follow-ons to the CDC 1604 and CDC 924 systems. Over time, a range of machines were produced - divided into the 'upper 3000 series' and the 'lower 3000 series'. CDC phased out production of the 3000 series in the early 1970s...
  
   series
  • CDC 3600 1963
  • CDC 3200 1964
  • CDC 3400,3800 1965
  • CDC 3100,3300 1965
• Elliott
  Elliott Brothers (computer company)
  -Elliott Brothers Ltd:Elliott Brothers Ltd was an early computer company of the 1950s–60s in the United Kingdom, tracing its descent from a firm of instrument makers founded by William Elliott in London around 1804. The research laboratories were based at Borehamwood, originally set up in...
  
   503
• Ferranti-Packard 6000
  Ferranti-Packard 6000
  The FP-6000 was a second generation mainframe computer developed and built by Ferranti-Packard in the early 1960s. It is particularly notable for supporting multitasking, being one of the first commercial machines to do so...
  
  
• Ferranti Argus
  Ferranti Argus
  Ferranti's Argus computers were a line of industrial control computers offered from the 1960s into the 1980s. They were widely used in a variety of roles in Europe, particularly in the UK where they continue to serve as monitoring and control systems for nuclear reactors.-Original series:The...
  
   300
• GE-200 series
  GE-200 series
  The GE-200 series was a family of small mainframe computers of the 1960s, built by General Electric.The main machine in the line was the GE-225. It used a 20-bit word, of which 13 bits could be used for an address. Along with the basic CPU the system could also include a floating-point unit, or...
  
  
• UNIVAC 418
  UNIVAC 418
  The UNIVAC 418 was a transistorized, 18-bit word core memory machine made by Sperry Univac. The name came from its 4 microsecond memory cycle time and 18-bit word. The assembly language for this class of computers was TRIM III and ART418....
  
  
• PDP-6
  PDP-6
  The PDP-6 was a computer model developed by Digital Equipment Corporation in 1963. It was influential primarily as the prototype for the later PDP-10; the instruction sets of the two machines are almost identical.The PDP-6 was DEC's first "big" machine...
  
  
• BESM
  BESM
  BESM is the name of a series of Soviet mainframe computers built in 1950-1960s. The name is an acronym for "Bolshaya Elektronno-Schetnaya Mashina" , literally "Large Electronically Computing Machine". The series began as a successor to MESM...
  
   3M, 4 circa 1963

1964

• IBM 7094 II
  IBM 7090
  The IBM 7090 was a second-generation transistorized version of the earlier IBM 709 vacuum tube mainframe computers and was designed for "large-scale scientific and technological applications". The 7090 was the third member of the IBM 700/7000 series scientific computers. The first 7090 installation...
  
  
• Model 109
  Model 109
  The Model 109, or Number 109, was a series of mainframe computers designed and built in the People's Republic of China, starting in 1964.*The Model 109-B, China's first transistor computer was created in 1965....
  
  
• GE-400 series
  GE-400 series
  The GE-400 series were Time-sharing Information Systems computers by General Electric introduced in 1964 and shipped until 1968.They used 24-bit words storing binary words, 4 6-bit BCD characters or 4 signed decimal digits...
  
  
• English Electric KDF8
• English Electric KDF9
  English Electric KDF9
  KDF9 was an early British computer designed and built by English Electric, later English Electric Leo Marconi, EELM, later still incorporated into ICL. It first came into service in 1964 and was still in use in 1980 in at least one installation...
  
  
• SDS 930
  SDS 930
  The SDS 930 was a commercial computer using bipolar junction transistors sold by Scientific Data Systems.It was announced in December 1963, with first installations in June 1964.-Description:An SDS 930 system consisted of at least three standard The SDS 930 was a commercial computer using bipolar...
  
  
• CDC 6600
  CDC 6600
  The CDC 6600 was a mainframe computer from Control Data Corporation, first delivered in 1964. It is generally considered to be the first successful supercomputer, outperforming its fastest predecessor, IBM 7030 Stretch, by about three times...
  
  
• Titan (computer)
  Titan (computer)
  Titan was the prototype of the Atlas 2 computer developed by Ferranti and the University of Cambridge Mathematical Laboratory in Cambridge, England...
  
   (Atlas 2)
• Ural (computer)
  Ural (computer)
  Ural is a computer series built in Soviet Union.- History :The Ural was developed at the Electronic Computer Producing Manufacturer of Penza in the Soviet Union and was produced between 1959 and 1964. In total 139 were made...
  
   11, 14
• Bunker Ramo Corporation
  Bunker Ramo Corporation
  Bunker Ramo Corporation was founded by George M. Bunker and Simon Ramo in 1964, jointly owned by Martin-Marietta and Thompson Ramo Wooldridge TRW . The resulting company, Bunker-Ramo, was based in Trumbull, Connecticut....
  
   BR-133 aka AN/UYK-3

1965

• GE-600 series
  GE-600 series
  The GE-600 series was a family of 36-bit mainframe computers originating in the 1960s, built by General Electric . When GE left the mainframe business the line was sold to Honeywell, who built similar systems into the 1990s as the division moved to Groupe Bull and then NEC.-Architecture:The 600...
  
    (some integrated circuits)
• NCR 315-RMC
• PDP-8
  PDP-8
  The 12-bit PDP-8 was the first successful commercial minicomputer, produced by Digital Equipment Corporation in the 1960s. DEC introduced it on 22 March 1965, and sold more than 50,000 systems, the most of any computer up to that date. It was the first widely sold computer in the DEC PDP series of...
  
  
• IBM M44/44X
  IBM M44/44X
  The IBM M44/44X was an experimental computer system from the mid 1960s, designed and operated at IBM's Thomas J. Watson Research Center at Yorktown Heights, New York. It was based on an IBM 7044 , and simulated multiple 7044 virtual machines , using both hardware and software. Key team members were...
  
  
• TRASK
  Trask
  -People with the surname Trask:* Diana Trask, a singer* Elbridge Trask, a mountain man* Eliphalet Trask, a politician* Gustavus Trask, the governor of Sailors' Snug Harbor* Haunani-Kay Trask, an activist and writer* Larry Trask, a linguist...
  
  , transistor version of BESK
  BESK
  BESK was Sweden's first electronic computer, using vacuum tubes instead of relays. It was developed by Matematikmaskinnämnden and during a short time it was the fastest computer in the world. The computer was completed in 1953 and in use until 1966...
  
  http://fof.underhuset.com/IFindex.lasso?id=00759ahttp://www.nada.kth.se/om/historik/text.htmlhttp://fof.underhuset.com/IFindex.lasso?id=00514

1966

1967

• CDC 6400
  CDC 6400
  The CDC 6400, a member of the CDC 6000 series, was a mainframe computer made by Control Data Corporation in the 1960s. The central processing unit was architecturally compatible with the CDC 6600...
  
  
• CER-22
  CER-22
  CER model 22 was a transistor based computer developed by Mihajlo Pupin Institute in 1967. It was originally intended for banking applications and was used for data processing and management planning in banks, trade and utility companies in Belgrade.Three CER-22 computers were purchased by...
  
  

1968

• PDP-10
  PDP-10
  The PDP-10 was a mainframe computer family manufactured by Digital Equipment Corporation from the late 1960s on; the name stands for "Programmed Data Processor model 10". The first model was delivered in 1966...
  
   (first model only - later versions used ICs)
• BESM
  BESM
  BESM is the name of a series of Soviet mainframe computers built in 1950-1960s. The name is an acronym for "Bolshaya Elektronno-Schetnaya Mashina" , literally "Large Electronically Computing Machine". The series began as a successor to MESM...
  
  6 (first model only - later versions used ICs)
• Moscow Power Engineering Institute M-54