A SURVEY OF EARLY POWER TRANSISTORS by Joe A. Knight TEXAS INSTRUMENTS 1950s/60s GERMANIUM POWER TRANSISTORS
ABOVE, L-to-R:   Along with TI's development of high power transistors, they continued to refine their  medium power size devices.  In 1957, they upgraded the older 951-953 silicon devices with the new "2N339 - 2N343" (shown above) silicon transistors, now rated at 1 watt of dissipation.  While a little larger in size they did not need the heat sink tab required of the 950 series and could now be circuit board mounted.
ABOVE (LEFT PHOTO) L-to-R: In late 1957 TI brought out what might be called their finest achievement in silicon transistor advancement.  The above shown diffused-base type "2N497" and "2N498" were built in the small TO-5 package but dissipated 4 watts of power.  Quite an achievement in only 3 years of silicon technology development. ABOVE (RIGHT PHOTO) L-to-R:  Finally, by late 1958, TI recognized the need for product somewhere in-between the medium power and high power devices and so came out with an "intermediate power" stud-mounted diffused-base silicon series called the "2N1047 (first item) - 2N1050" devices, all rated at 40 watts dissipation.  Again, a monumental achievement from such a compact package that's even smaller than a dime.  The second item is an in-house numbered version, called the SP1178 (SP= Special Products? Silicon Products?).  Texas Instruments would go on into the 60's to further develop and refine both their Germanium and Silicon line of Power Transistors, using new mesa and epitaxial technologies to achieve even greater power ratings and more efficient packaging. ______________
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