Discrete Semiconductors

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Bell Telephone Laboratories A-2277
 Bell Telephone Laboratories A-2277

The Bell Telephone Labs A-2277 is an undocumented prototype transistor in a TO-38 package, likely a diffused junction device similar to the Western Electric 2N1072 or 2N1645. Unlike most production devices which have a lacquered or gold-plated copper case, the A-2277 has an unusual gunmetal grey finish which is known to be used with Western Electric internal-use types manufactured between 1960 and 1963.

Bell Labs prototypes manufactured at the Murray Hill facility featured an M- part number prefix, while prototypes manufactured at Western Electric's Allentown plant had a corresponding A- prefix. Some of Bell's earliest transistors were mass produced by Western Electric under a prefixless version of their four-digit Bell part number, but most production types were assigned either a Bell System internal part number, a government account number or a traditional RETMA number.

If you can provide information about this rare device, please contact us.

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General Electric 2N1086
 General Electric 2N1086

Introduced around 1958, the General Electric 2N1086 is a 65mW germanium NPN grown junction transistor designed for use as an oscillator in AM radio receivers. The 2N1086 was intended to replace the earlier 2N168A, and was used in a number of early transistor radios. This device uses the same style of elliptical metal canister as Western Electric's early NPN grown junction transistors.

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General Electric 4JA60AX544
 General Electric 4JA60AX544

The General Electric 4JA60AX544 (base P/N 4JA60) is a high current silicon diode of unknown specification.

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Honeywell H10A1XOC
 Honeywell H10A1XOC

The H10A1XOC appears to be an uncharacterized variant of the Honeywell H10 power transistor, introduced in 1957. The H10 is a large germanium PNP power transistor with a 15W power dissipation rating, hook lug leads and a large threaded mounting lug. Honeywell began producing power transistors in 1953 for in-house use in their various industrial automation systems. Although Honeywell was an early pioneer of germanium power transistors, their devices are uncommon and often overlooked in the pantheon of early transistor development.

Honeywell later produced similar commercial devices with standard RETMA part numbers: the 2N574 and 2N575, both rated at 25W.

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Hitachi DSS100A2R
 Hitachi DSS100A2R

The Hitachi DSS100A2R is a high voltage diode of unknown specification. If you can provide information about this device, please contact us.

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Kearfott 2N110
 Kearfott 2N110

Introduced by Western Electric in 1955, the 2N110 is a germanium point contact switching transistor similar to the original 2N21. Perhaps the most robust point contact device ever built, the 2N110 is intended for severe military applications and is useful over a wide temperature range. The example pictured here was manufactured by Kearfott in 1970, long after point contact transistors had become obsolete. Kearfott is the only second source for the 2N110 currently known.

Western Electric 2N110 Datasheet (PDF)

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Motorola 2N554
 Motorola 2N554

Introduced in the late 1950s, the Motorola 2N554 is a germanium PNP power transistor in a gold-plated TO-3 package. The 2N554 was originally intended for automotive applications, and was also the transistor featured in the first published design for a transistorized model train throttle.

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Philco 2N1158A
 Philco 2N1158A

The Philco 2N1158A is a germanium PNP micro alloy diffused transistor (MADT), an improved type of surface barrier transistor capable of operating at frequencies in excess of 200MHz. The example shown here is a U.S. Army variant.

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Philco HAW1943
 Philco HAW1943

The Philco HAW1943 is an unidentified device, but appears similar to the 2N1158A MADT.

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RCA 2N688
 RCA 2N688

The RCA 2N688 is an early silicon diffused junction thyristor in a TO-48 package, rated at 600V, 25A. The 2N688 is designed for high power switching applications.

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Raytheon CK718
 Raytheon CK718

Introduced in late 1952, the Raytheon CK718 germanium PNP transistor is believed to be the first mass-produced junction transistor. The CK718 was not made available to consumers, but was instead supplied exclusively to a number of hearing aid manufacturers.

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Raytheon CK722
 Raytheon CK722

The Raytheon CK722 germanium PNP transistor is a low performance bin of the CK718 shown above. The CK722 is regarded as the first low cost transistor available to consumers, and is the transistor used by Bulova engineer Max Hetzel during prototype development of the Accutron electronic timepiece.

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Raytheon 2N132
 Raytheon 2N132

The Raytheon 2N132 germanium PNP junction transistor is a miniaturized RETMA-numbered version of the CK725, first introduced in 1954. Designed for use in audio frequency preamplifiers, the 2N132 is a minuscule device. Despite its early metal can construction, its size is comparable to modern small signal transistors.

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Rheem Semiconductor RT5202
 Rheem Semiconductor RT5202

The Rheem RT5202 is a silicon NPN transistor of unknown specification, in a standard TO5 package.

Rheem Manufacturing Company, best known as a manufacturer of water heaters, followed in the footsteps of Fairchild Camera & Instrument by backing an early transistor start-up division in Silicon Valley. In March 1959, Fairchild Semiconductor's general manager Ed Baldwin and several other employees abruptly resigned, and established Rheem Semiconductor Corporation in Mountain View, California. Rheem soon began producing mesa transistors based on Fairchild's design. Fairchild then sued Rheem, and discovered intellectual property which had been removed from Fairchild by Ed Baldwin and his group. Fairchild and Rheem ultimately settled out of court, primarily due to uncomfortable similarities between Ed Baldwin's illicit activities and the events which led to the formation of Fairchild Semiconductor. Rheem ultimately agreed to not produce mesa transistors based on Fairchild's design.

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Sprague 2N128
 Sprague 2N128

Philco introduced the germanium PNP surface barrier transistor (SBT) in late 1953. SBTs gained rapid popularity due to their high frequency performance, and established Philco as a key early transistor manufacturer. The 2N128 is an early commercial SBT, introduced by Philco and later replicated first by Sprague and then other manufacturers.

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Sylvania 1N415C
 Sylvania 1N415C

The Sylvania 1N415C is a silicon point contact microwave mixer diode designed to operate at X-band frequencies. The example shown here is a pair matched at the factory for output voltage.

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Texas Instruments J44
 Texas Instruments J44

The Texas Instruments J44 is an early device of unknown specification. It is likely a silicon bipolar junction transistor.

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Tung-Sol TS-1453
 Tung-Sol TS-1453

The Tung-Sol TS-1543 is an uncharacterized power transistor in a TO-36 case. This device appears to be similar to the Tung-Sol second-source variants of the Delco 2N174 and 2N441, large germanium power transistors rated for 15A.

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Western Electric 2N29
 Western Electric 2N29

The Western Electric 2N29 is an early production example of a germanium NPN grown junction transistor. In 1955, Western Electric introduced their first two production grown junction transistors: the 2N27 and 2N28. The 2N29 followed in 1957. All three of these devices were derived from the Bell Labs M-1752 grown junction prototype, but the 2N29 was considered suitable for military use.

Prior to Fairchild's introduction of the planar transistor in 1959, semiconductors lacked a protective silicon dioxide passivation layer to protect against internal contamination of the base-collector junction. Many of these early semiconductors featured a hermetically sealed metal canister, often with an evacuation nipple.

Western Electric 2N29 Datasheet (PDF)

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Western Electric 2N66
 Western Electric 2N66

Introduced in 1955, the 2N66 is Western Electric's first production power transistor. Derived directly from the Bell Labs M1777 power transistor prototype, the 2N66 is a general purpose germanium PNP alloy junction device, rated at 0.8W dissipation. The 2N66 established a package standard which would be used with a number of subsequent transistor types.

Western Electric 2N66 Datasheet (PDF)

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Western Electric 3N22
 Western Electric 3N22

The Western Electric 3N22 is an unusual germanium grown junction tetrode transistor with two leads connected to its base. This tetrode configuration was a solution to poor frequency response in grown junction transistors, by which higher frequencies could be obtained by biasing the second base electrode. Vestigial clipped fourth electrodes can also be found on various Western Electric triode transistors from the era, such as the GA-52609.

Western Electric 3N22 Datasheet (PDF)

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Western Electric 2N559
 Western Electric 2N559

The Western Electric 2N559 diffused-junction germanium PNP transistor is perhaps the first military-rated computer transistor. Released in 1957, the 2N559 is a rugged, highly reliable, high speed switching transistor, capable of operation in excess of 400MHz. The 2N559 features a diffused-junction mesa construction, is highly miniaturized, and is a distinctly mature device for its time.

The 2N559's numerous high-performance features, as well as Western Electric's ability to produce them in large quantities, resulted in their use in the Remington Rand UNIVAC Target Intercept Computer (TIC), whose logic circuitry employed 20,000 2N559 transistors.

Mechanization of Semiconductor Devices: 2N559 & 2N1094 - Quarterly Progress Report 17 (PDF)
Mechanization of Semiconductor Devices: 2N559 & 2N1094 - Quarterly Progress Report 22 (PDF)
Obsolete Lower Power & Switching Transistors Datasheet (PDF)

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Western Electric 2N1072
 Western Electric 2N1072

The Western Electric 2N1072 is a diffused junction silicon NPN mesa power transistor, specially developed for use as a core memory driver in the Nike Zeus anti-ICBM missile system. The 2N1072 is a rugged device capable of high current, high frequency operation in high temperature environments, and was the first device to use the TO-38 package, a cold welded, vacuum-sealed canister.

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Western Electric 7B
 Western Electric 7B

One of the last alloy junction devices produced by Western Electric, the 7B is an intermediate-power germanium PNP transistor intended for Bell System internal use. The 7B pictured here is an earlier example with a P-5 canister painted in grey lacquer, while later examples of the 7B are packaged in an updated P-6 canister with no evacuation nipple. Soon after the introduction of the 7B and allied devices in the late 1950s, Western Electric shifted production to diffused junction and planar transistors.

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Western Electric 9A
 Western Electric 9A

Introduced in 1958, the Western Electric 9A is a 30W PNP alloy junction germanium transistor in a TO-32 package, manufactured for in-house use. The 9A was derived from the 2074 development type, and was intended to replace the earlier 6A, a 2W audio-freqency device. The 2074 was a dramatic improvement in dissipated power over intermediate power devices like the 2N66 and GA-52830. In addition to the 9A, Western Electric developed the 2N463, a RETMA-numbered derivative of the 2074 rated at 35W.

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Western Electric 20D
 Western Electric 20D

The Western Electric 20D is a diffused junction silicon NPN power transistor rated at 1.5W. The 20D was widely employed in Bell System telephone equipment, and uses the same TO-38 canister construction as the 2N1072.

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Western Electric F-51618 & F-51619
 Western Electric F-51618 & F-51619

Devices included in this entry:

Western Electric F-51618 NPN germanium alloy junction transistor
Western Electric F-51619 PNP germanium alloy junction transistor (pictured in thumbnail)


The Western Electric F-51618 & F-51619 are a complementary pair of germanium alloy junction transistors, developed in the late 1950s for the Bell #1 Electronic Switching System (1ESS). The F-51618 (BTL A-2037) is a NPN device, while the F-51618 (BTL A-2038) is a PNP device of similar construction. The F-51618 & F-51619 have the unique feature of dual redundant emitter and base internal leads.

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Western Electric GA-52609 & GA-53270
 Western Electric GA-52609 & GA-53270

Devices included in this entry:

Western Electric GA-52609 NPN alloy junction transistor
Western Electric GA-53270 NPN alloy junction transistor (pictured in thumbnail)


Introduced in 1955, the Western Electric GA-52609 is an early NPN alloy junction transistor designed for audio and carrier frequencies. The original specification for the GA-52609 indicates a hermetically sealed canister with an evacuation nipple, but by 1956 this case style had been abandoned in favor of an improved nippleless canister.

The GA-53270 is a direct replacement for the GA-52609, with a slightly higher alpha cutoff frequency.

Western Electric GA-52609 Datasheet (PDF)

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Western Electric GA-52830 & GA-53242
 Western Electric GA-52830 & GA-53242

Devices included in this entry:

Western Electric GA-52830 germanium PNP power transistor
Western Electric GA-53242 germanium PNP power transistor


Originally developed at Bell Telephone Labs as the M-2012, the Western Electric GA-52830 is an early PNP germanium power transistor, rated at 0.5W dissipation with switching speeds up to 4MHz. This combination of high gain and high speed made the GA-52380 suitable for driving core memory circuits in early transistorized computers, but its status as a developmental part number confined its use to government-funded prototypes. The GA-52830 was employed in a number of early experimental computers, including the MIT Lincoln Laboratory TX-2 and the TRADIC Leprechaun.

Western Electric later introduced the GA-53242, a production version of the GA-52830.

Western Electric GA-52830 Datasheet (PDF)

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Western Electric GA53677
 Western Electric GA53677

The Western Electric GA53677 is a germanium PNP transistor of unknown specification. Much like Hewlett-Packard, Western Electric's history is riddled with unidentified in-house part numbers. The uncharacterized GA53270 is a typical example of this phenomenon. Many Western Electric semiconductor part numbers are prefixed with GA, GF or F, generally accepted to indicate the parts were produced for a military or government contract. Other than the part number, the GA53677 appears externally identical to other Western Electric transistors from the same era.

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JAN2N1016C (Unknown Mfr.)
 JAN2N1016C (Unknown Mfr.)

Originally introduced by Westinghouse in 1959, the 2N1016C is a high purity silicon power transistor with a 1500W power dissipation rating. The example pictured here is a JAN variant, and the manufacturer is currently unknown.

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