Because I'm based in the UK, it is not so easy for me to find rare US transistors. Nevertheless I have obtained some, and this page shows the earliest and rarest US transistors that I have had the good fortune to find, including some intriguing ones that I cannot identify but believe to be very early types. For many of these devices there is little information available, so if you have any, please contact me using the email button on the left. If you have any old or unusual germanium transistors or diodes for sale or exchange, I would be very keen to hear from you.
PS please excuse the watermarks, I'm slightly fed-up of finding my images used on the Web without acknowledgement. If you want to use any for legitimate purposes, and are happy to acknowledge me, just contact me and I'll email them to you.
The Raytheon CK703 was the first ever commercial transistor, a point-contact type from about 1951 preceded only by Western Electric research types. The example shown is unused in its original carton. It is a cartridge type but I'm not sure what socket it plugged into.
This is a rare box of Western Electric type 1698 point-contact transistors.
The Sprague type 5A is a particularly rare point-contact transistor. My image shows one, although the printing is smudged and doubled up, and the type number appears to be T5.
The Sylvania GT442 is a point-contact transistor in what appears to be a hollow plastic case. I'm not sure how hermetic this would be.
This unknown device is clearly a point-contact transistor in a Type A cartridge case. It has a plastic sleeve marked 01 X3 and underneath that is handwritten 51071. If you have any idea what it is please contact me using the email button above.
The Motorola EP-7 is a rare point-contact transistor in a rather large cylindrical case. I have no data on it, if you have any please contact me using the email button above.
This Western Electric GA51984 point-contact transistor is a Type A cartridge fitted into a clip for the base connection and with long leads soldered to the pins. I believe that it is a military equivalent to the 2N21. I also have a GA52996 point-contact transistor in a grey-painted normal can like the 2N67 or 2N110.
This Sylvania GT-372 is a very rare point-contact type. I have no data on it, if you have any please contact me using the email button above.
The RCA TA165 is a point-contact transistor in a nice transparent plastic case so you can see its internal construction.
These Hughes-Aircraft HA5001 - HA5003 juncion transistors look more like diodes. They plug into a special clip that provides the third connection. The coloured stripes identify the type. Hughes used similar co-axial packages for later types, but usually with a soldered third wire.
These Hydro-Aire HF-1 JP-1 and J-3 are interesting examples from this short-lived semiconductor manufacturer.
The Germanium Products RDX300 is an early tetrode transistor.
The RCA SX160 is a germanium junction transistor prototype from about 1953.
National Union Electric Corp. produced a small number of transistors in rather basic plastic cuboids coloured emerald green with printing in silver. I'm lucky to have the T21A shown and I'm seeking more examples of it or of other NU types, so if you have any for sale or trade (I can exchange for other rare early transistors) then please contact me using the email button above.
The RCA TA153 is a prototype junction transistor from about 1952.
My database contains notes saying that this medium-sized device is an IBM X-4 but I cannot remember where I obtained this information. If you know anything about it, please contact me using the email button above.
This is a Bell Telephone Labs type M1752 junction transistor, as you can tell by the coloured dots purple-green-red. It was the first junction type ever made.
This Western Electric 3N22 is a double-base tetrode transistor. I have a few of these all dated 1956.
I believe that this strange device is a Transistor Products X-107 although it must be a research prototype as it is lacking a base plate and you can see right in to the interior with the germanium die, to which the leads attach. If you know anything about it, please contact me using the email button above.
The Texas Instruments X2 is a small medium-power germanium experimental type from about 1954. TI tried several ways of welding or clipping heatsinks onto the oval SO-4 type can.
The person who sent me these Motorola XN-1 transistors said that this type was the company's first. I'm not sure how that fits with the Motorola point-contact type EP-7 shown above. I also have some identically-shaped Motorola types marked XN-2 and 2NJ2, which I was told are the same device. If you know anything about any of these, please contact me using the email button above.
Transitron made a number of interesting low-numbered 2N types such as this 2N83 and a similar 2N84. These seem to have had two different shapes: cylindrical like mine or else with a domed top. I'm seeking more examples of it or of other early Transitron types, so if you have any for sale or trade (I can exchange for other rare early transistors) then please contact me using the email button above.
This Transitron 2N85 is a rare type in an SO-4 oval can welded to a heatsink bar.
These cylindrical types are Motorola power transistor prototypes. I have no data on them, if you have any please contact me using the email button above.
Clevite Transistor Products specialised in early power transistors such as this CTP1002 in a unique case style. I'm seeking more examples of it or of other Clevite types, so if you have any for sale or trade (I can exchange for other rare early transistors) then please contact me using the email button above.
Minneapolis-Honeywell were another manufacturer that specialised in early power transistors in their own H series, and types such as this 2N57.
The Radio Receptor RR66A is a very early phototransistor with a nice glass dome over the germanium die.
These Radio Receptor CD6 diodes are quite rare. I have no data on RR devices, apart from a few very early transistors, so if you know about them, please contact me using the email button above.
I was told that this unmarked transistor is a Philco AUDIO type. It seems to have a shell in two pieces crimped together, as though there is a smaller device inside. If you have any idea what it is please contact me using the email button above.