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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: Not to be out-down by the competition, TI did manufacture it's own line of Germanium Power Transistors. By early 1956 TI had developed a large round can enclosure type called the PNP type "356" and the "356A", both rated at 12 watts dissipation. By mid-1956 these evolved into their first TO-3 devices, the "2N250" (first item) and the "2N251" and were now all rated at 25 watts dissipated power. In 1957, TI released two more TO-3 types, the "2N456" (middle item and cut-open last item) and the "2N457", both rated at 35 watts (and later in 1958 at 50 watts) dissipation.
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ABOVE, L-to-R: Continuing their search for an even higher power output device finally culminated in early 1957 with the diffused-junction Power Transistor silicon types, the "2N389" (the first item with cut-open middle item) and the "2N424" (identical - not shown). These were both initially rated at a whooping 37.5 watts (& later in 1958 rated at 85 watts!) of dissipation in a square package about half the volume of a TO-3 device. This was also called the in-house model "J231", far right. TI had finally produced something which showed the rest of the world what their investment in silicon technology was all about.
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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 4 |
