by Joe Knight




I have already sent you the write-up for the early "Transistor Products" (Power Trannies) linee-up which covers the era from 1953-1955.  This current period covers the next generation of power transistors from late 1955 to 1957.  It was at this time that the Clevite Corporation decided to call the product line by the full "Clevite Transistor Product" name.  Even though they had bought Transistor Products back in 1953 the only indication of the new ownership was the use in 1954 of the "C/TP" logo that appeared on their later "X-" series of products.   So ads in 1956 started using the new "Clevite Transistor Products" name and their products from then on were just marked "Clevite" or "CTP".


TOP ROW, L-TO-R:  We know from Marrows 1956 book, "Transistor Engineering", that Clevite TP first developed the wide flange top-hat power transistor in early 1956.  The far left item is probably an early pre-production device from late 1955 as it's base is made of copper. All the later ones were made of steel.  The far right two items are a Clevite CTP-1002, dated from 26th week, 1956.  This is the first high power transistor from the new product design, rated at 25 watts dissipation, on 28 volts, as was the new CTP-1003.  Additionally, they released a 12 volt line called the CTP-1004, CTP-1005 and CTP-1006, all rated at 25 watts dissipation.  These were all PNP Germanium types. All of these had the exhaust tip on the top-hat cover and unlike CBS, did not cover the tip with anything.


BOTTOM ROW, L-TO-R:  By mid 1956 Clevite TP had come out with their own TO-3 line of transistors. First was the 2N257, middle item, and this was followed by the 2N268 and 2N268A - all rated at 25 watts dissipation.  By late 1956 the 2N297 (far right) and the 2N297A were released, rated at 35 watts. As can be seen in the early 1956 devices, far left two and the far right, Clevite was still using a top exhaust construction method as the round exhaust dimple shows on the top cover, although without any tip. The far left two items are likely early production samples as they do not have any recognizable numbers but are both from 1956.




Go To Clevite Transistor Products Early Power Transistors, Page 2



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Joe Knight Early Power Transistor History – CLEVITE TRANSISTOR PRODUCTS