Transistors and Diodes

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Raytheon CK718 & CK722

Released in 1953, the blue painted Raytheon CK722 PNP transistor is quite possibly the most famous and beloved transistor ever made. Initially made in a clear plastic painted package, the CK722 was part of a family of parts originally derived from the CK718 hearing aid transistor. Early transistor production was a slapdash affair at best, and many of the CK718's that Raytheon produced did not meet the advertised specifications. These low-bin parts were packaged under a different part number, CK722, and sold as low performance devices specifically for the hobby market. As a result, an entire generation of electronics enthusiasts cut their teeth on blue painted CK722 transistors. The CK722 became so iconic that Raytheon began to paint their other semiconductors in the same shade of blue to capitalize on the popularity of the device.


Raytheon CK718 & CK722 Transistors
Raytheon CK782

The CK782, made by Raytheon, is a germanium PNP transistor intended for use in early hearing aids. First released sometime around 1955, the early CK782's make use of Raytheon's iconic blue paint job, popularized by the hobbyist friendly CK722 shown above. The CK782 is quite tiny for a metal can transistor, rivaling the size of later devices in TO-92 plastic enclosures.


Raytheon CK782 Transistor
Teledyne TR1002 Fetron

Devices included in this entry:

Teledyne TR1002 (7 pin hermetic package, pictured in thumbnail)
Western Electric KS 21073 (7 pin hermetic package)

During the twilight of the electron tube era, many companies produced solid state tube replacements; semiconductor devices designed to mimic the shape and function of an electron tube. One such device was the Fetron, a metal can semiconductor that resembles a TO-5 transistor scaled up to comic proportions. Believed to have been originally produced by Western Electric, Fetrons were intended to replace the large number of glass electron tubes used in legacy telephone switching systems. The example shown here, a TR1002 solid state diode produced by Teledyne, is a 7 pin device intended to be a drop in replacement for a 6AL5 electron tube. The inside of the can is mostly empty space intended to make the device feel more 'tube-like', a ceramic wafer hybrid microcircuit is preformed to the bottom of the can and attached to the leads with bond wire. A plastic spacer attached to the base prevents the tube's metal case from shorting out when pressed against older legacy tube sockets.

Fetrons are probably best known for their use by Heathkit, which marketed a solid state conversion kit for their line of tub-based voltmeters. This kit could convert Heathkit and competitor VTVM's over to solid state components, and included a TR1002 diode as well as a 9 pin TR1119 triode.


Teledyne TR1002 Fetron Solid State Tube Replacement (TR1002 & KS 21073)
Sylvania 2N35

The Sylvania 2N35 is an early consumer-grade germanium transistor, notable for its NPN construction at a time when most of the available devices were of PNP construction. Released in 1953, the 2N35 was a competitor to the popular Raytheon CK722. Like many early transistors, the 2N35 is packaged in a small elliptical metal can, which can mate to common transistor sockets of the era.


Sylvania 2N35 Transistor
General Electric 2N43

The 2N43, along with the 2N44 and 2N45, were General Electric's first commercially produced alloy junction transistors. First produced in 1953, the 2N43 used a vacuum-sealed glass and metal package designed by Conrad Zierdt, a General Electric production engineer. This packaging, which abandoned the failure-prone epoxy and potting compounds of other early transistors, significantly lowered electrical variation between devices. A variant of this transistor, the 2N43A, was the first transistor to be qualified for use by the USAF.


General Electric 2N43 Transistor (2N43A)
Raytheon CK784

In the early days of the transistor era, Raytheon produced a number of small audio frequency devices for use in the hearing aid market. The Raytheon CK784 is one such device; a tiny metal can PNP transistor intended for use in audio amplifiers. The CK784 is approximately half the size of Raytheon's popular hobbyist-friendly CK722 transistor, and is small enough to encroach on the size of a modern TO-92 device. Raytheon's iconic blue paint, also popularized by the CK722, is present and accounted for.


Raytheon CK784 Transistor
Siemens TF65

The TF65 is a germanium junction transistor that introduced in 1957. This transistor was made in both a silver and black cased version; the black version is shown here. This model of transistor is best known for it's use inside Kundo's line of electromagnetic pendulum clocks, which make use of the transistor in the pendulum drive circuit. The TF65 is a common point of failure in these clocks, requiring replacement with a more readily available germanium part number, the AC125 being the most common choice.

Siemens TF65 Transistor
Mullard ORP61

The ORP61, manufactured by Mullard, is a cadmium sulfide photocell in a tiny tubular package. The clear case of this device mimics the shape of many earlier transistors manufactured in Europe and Great Britain, a fact which causes many collectors to mistakenly identify this part as a diode or transistor. The strange internal construction of the ORP61 does little to help in identification; this part lacks the typical serpentine pattern of the average photo-resistor, instead a translucent block is bonded across two leads at the head of the device. The ORP61 has a nominal resistance of 60kOhms and a maximum power rating of 70 mW at 350 volts DC.

Mullard ORP61 Photocell
Fairchild FPA 700

The Fairchild FPA700 is a very early phototransisor array, which was first produced in the late 1960s. Intended for use in paper-tape reading machines, the FPA 700 is constructed out of nine NPN phototransistor dies packaged in a crude plastic encapsulation. Each phototransistor is protected by a layer of transparent resin and is wired to a dedicated pair of gold leads. The FPA 700 is rated for a maximum of 20 volts and 25ma of current per phototransistor cell. The example shown here has a date code of 1969.


Fairchild FPA 700 Phototransistor Array
Raytheon CK2000

If a steampunk fetishist was tasked with building an old-timey analog optoisolator, a raysistor might be the result. Raysistors are primitive optical isolation components that contain an incandescent bulb and a CDS photoresistor closely coupled in a blob of clear epoxy. The example shown here, a CK2000 manufactured by Raytheon, has had it's metal cover removed so the internal structure can be seen. Raysistors have one immediately obvious disadvantage over optoisolators... incandescent lamps can and do burn out. For this reason the CK2000 is designed to be a user replaceable part, and mates with a special four-pin socket that was provided in the same packaging.

Raytheon also produced much longer lasting raysistors that utilized a neon bulb instead of an incandescent lamp as the light source. This eliminated the threat of a burned out lamp filament, but resulted in a part with much more limited analog capabilities.


Raytheon CK2000 Raysistor
Western Electric 2N559

The Western Electric 2N559 is an early germanium PNP transistor that was likely first produced in 1959. Noteworthy for it's use in the US Nike Zeus missile defense system, the 2N559 was first produced in a gold plated metal can enclosure with an attached evacuation pip. After 1961, Western Electric eliminated the pip and switched to the use of a barium hydroxide alloy sponge, which was sealed within the transistor package to absorb any latent gasses. These later manufacture 2N559's are packaged in a black painted metal can, similar in size to a standard TO-18 transistor package. The 2N559 was manufactured at Western Electric's Laureldale plant.


Western Electric 2N559 Transistor
Philco 1N82

The 1N82 is a mid-1950s era germanium diode intended as a low loss mixer for use in television receivers. The 1N82 has a classic 'cat whisker' point contact, which can be seen pressing against the diode's square germanium crystal through the glass housing. Unlike some earlier devices, no provision has been included for manual adjustment of the point contact's position after installation of the diode in it's target system.


Philco 1N82 Transistor
Burroughs B5000 Diode Logic Module

This early diode module is a plug-in logic element from a Burroughs B5000 mainframe. The B5000, which was released in 1961, was the first computer produced in-house by the Burroughs corporation. The B5000 was assembled from large numbers of modules such as this, which contains 8 diodes mounted in a diallyl pthalate carrier. An array of pins along the edge of the module connect it to the rest of the computer system.

The Burroughs B5000 also contained larger plugin 'cordwood' modules, which contained transistors and passive components wired between two parallel circuit cards. Each module had a pin grid array and a metal handle on opposing faces, for easy removal.


Burroughs B5000 Diode Logic Module
United Detector Technology UDT PIN-10D

This is a PIN-10D planar silicon photodiode, a monstrous solid state photon collector produced by the United Detector Technology. The active area of this device is over 11mm in diameter, and the silicon die is packaged in a large metal enclosure that would make any standard TO-5 photodiode feel positively emasculated. The PIN-10D does not have pins; instead a standard BNC socket connector has been incorporated directly into the device's package.


United Detector Technology UDT PIN-10D Planar Silicon Photodiode
Honeywell H5

The Honeywell H5 is an early power transistor which was released in 1956. The H5 is a germanium PNP device with a power rating of 10 watts, and is the first Honeywell power transistor to use hook lugs instead of flying leads. Honeywell originally developed this series of transistors for use in aircraft fuel systems; some versions had power dissipation ratings in excess of 50 watts.


Honeywell H5 Transistor
Honeywell H10

The Honeywell H10, first released in 1957, is a successor to the 1965-era H5 power transistor. The H10 is a large metal-can device with hook leads and a threaded lug for heatsink or chassis mounting. This transistor has a power rating of 15 amps, and was packaged in a case almost twice the diameter of the earlier H5. The example shown here is a undefined later variant, marked with the part number H10A1XOC.


Honeywell H10 Transistor
General Electric 2N188

The 2N188 is a relatively unremarkable early PNP transistor manufactured by General Electric. The 2N188 was intended to be used as a medium power audio frequency amplifier, and has fairly linear gain and output. This transistor is packaged in a top-hat package; earlier versions included a top nipple for evacuation, which was dropped in later revisions.

General Electric 2N188 Transistor

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