MEMORIES & BACKGROUND
Going way way back in the mists of time (when I was a youngster) I extracted a number of these transistors from some Tektronix equipment - this would have been around the mid 1970's. I remember these transistors being particularly obvious because of their packaging with the part number clearly stamped into the ceramic of the package. Funny enough, the manufacturer is not identified but there is a high chance it would have been either Motorola or Fairchild at the time.
The transistor type is really not that special, you can still purchase modern TO-92 versions but it was the packaging which took my interest ... prior to these TO-106 transistors, I was used to working with the OC series and AC12x series Germanium transistors in their 'tube like' Black casing, the SO-2 type.
Type number is clearly indicated but not the manufacturer, most likely these were produced by Motorola or Fairchild
This 2N3642 TO-106 packaging was transitional when moving over from the metal cans to the contemporary TO-92 or other injection moulded plastic packages.
The lower White section is ceramic, the transistor die is bonded directly to the ceramic base with a 'blob' of epoxy (Black) on the top to seal the die from the environment.
Why on earth do I keep such things? (You may wonder, puzzled)
Sustainability is the name of the game! Anything (that has been tested and still functioning properly) should be repurposed creating saving in wasted Ee and reducing the poisoning of our environment when items are buried in the earth at the local tip needlessly.
Never heard of Ee? It is a concept that creates a measurement of ALL things (not just electronics) that humans have made and the energy used in obtaining the raw material, processing the materials right through to a finished product and even should include the shipping of the item to the distributors/retailers.
If you would like to know more about Ee values, please take a look HERE
UNKNOWN MANUFACTURER - Silicon Transistor (1)
Country of origin is unknown but given the equipment it was extracted from and the users at the time of the TO-106 package, I feel confident that this transistor was manufactured in USA
Type: 2N3642
This transistor is obviously a 'pull', lifted off the single sided PCB used in those days.
This means the Gold plated leads are short, just enough to fit through a 3mm thick PCB (actual lead length is 4mm)
Being a used, pull, I have checked the basic parameters of the device ...
hFE 92
NPN
Vf 828mV
Current gain is fine, specifications indicate a minimum of 40 but the Vf is interesting. Although this is definitely a Silicon based device, that reading was unexpectedly high ... I presume it is related to the doping used at the time.
There you have it! A nice little museum piece from 60+ years ago - great for the museum or someone who was rejuvenating REALLY OLD equipment and wanted to stay "pure" by using replacement components from the day, not modern substitutes.
The transistor is sitting on a bed of ESD foam to protect those short little legs and waits in anticipation of moving to a new workshop!
