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TRANSISTOR
MUSEUM™ Historic Transistor Photo
Gallery |
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HISTORIC
NOTES The
power handling capability of the first transistor types was quite limited,
with the result that the audio circuits in the first commercial transistor
radios produced power output of substantially less than one watt. RCA was very active in developing
transistors with improved power output and the SX155 from 1955 represents an early
success. This transistor was
described by Bob Slade in the “Recent Advances in Power Junction
Transistors”, which was presented at the Oct 25, 1955 meeting of the IRE
Professional Group on Electron Devices.
Construction details as well as performance characteristics are
captured in this paper. Also at RCA, H.C.
Lin developed several audio amplifier applications using this new
transistor type, including a 20 watt Class-B audio amplifier, documented in
“Transistors 1, RCA”, a 1956 compendium of early RCA transistor work. A limited number of samples of this
transistor type were produced, with hand-written labels of SX155 and
SX155A-D, depending on performance characteristics, appearing on the side of
the case. Most had serial numbers
written on the case top. The “SX”
designation was used at RCA to label experimental/pre-production
devices. |
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Copyright
© 2005 by Jack Ward. All Rights
Reserved. |
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