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A SURVEY OF EARLY POWER TRANSISTORS by Joe A. Knight TEXAS INSTRUMENTS 1950s/60s GERMANIUM POWER TRANSISTORS
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ABOVE, L-to-R: With the wide success and acceptance of their silicon devices TI quickly moved forward with releasing even more output transistors. By early 1955 they had released a new medium-power output series (shown above), called the "951" (similar to the X-15), "952" and "953". These were all rated at 3/4 watt dissipation and are often seen with and without the aluminum heat sink tab.
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ABOVE, TOP ROW, L-to-R: The first item shown is a developmental high power silicon device from mid- 1955. It's use of glass seals around the leads is unique and it's large copper diameter is the same as the next devices. This may have possibly been identified as the "X-36" output device. By the end of 1955 this lead to the first TI Silicon Power Transistor, the "970" (middle item) and it's cut-open interior (last item). This used the same similar glass seal for the bottom leads and was rated at 8.75 watts dissipation, much more than any other legitimate device then on the market.
ABOVE, BOTTOM ROW, L-to-R: In 1956 TI released a RETMA version of the “970” called the "2N122" (first item) and another in-house version called the "J252" (second item). Throughout it's long production history TI developed devices identified with their own ID numbers usually long before obtaining any RETMA/JEDEC registered numbers. Obtaining industry compatible devices seemed secondary to their marketing efforts. Being 'first to market' is an approach that has successfully served them well every time.
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COPYRIGHT © 2007 by Jack Ward. All Rights Reserved. http://www.transistormuseum.com/ Joe A. Knight Early Power Transistor History – TEXAS INSTRUMENTS Page 3 |
