A SURVEY OF EARLY POWER TRANSISTORS

by Joe Knight

CBS 1950s GERMANIUM POWER TRANSISTORS

 

 

Also in early 1956, along with the 2N155, CBS released the 2N156 and 2N158 types (third and fourth from left). The earliest examples came in white and were straight-sided and later, in 1957 and thereafter, were colored black with a slight step at the mid-section (see 2N158A, far right above). At this same time they released another "HD" item called the HD463, far left, which has short socket insert pins while all the others came with thin wire leads. Also in 1956, an early "DT" item was released, the DT-48, in gray. These were all Germanium PNP types, rated at 8.5 watts dissipation, same as the TO-3 types. All of these came with bolt holes for solid mountings to external heat sink surfaces. The earliest example shown, the white 2N158 from early 1956, does not have a diamond square around the CBS logo. All the later ones do, from late 1956 forward.

 

 

Later in 1958, CBS came out with a "LT5XXX" TO-3 series, not shown. As we know, CBS got out of the semiconductor business c. 1961/62 and so came to an end a once major transistor player, although not very successful apparently. Raytheon became a second source for the 2N156 and 2N158 items for those needing replacements down the road. Other companies second sourced the other early CBS TO-3 types.

 

 

 

 

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COPYRIGHT 2007 by Jack Ward. All Rights Reserved. http://www.transistormuseum.com/

Joe Knight Early Power Transistor History CBS Page 2