![]() ![]() Raytheon put little energy into promoting its RF transistors: this was because demand outstripped supply, a feature of the market in general. In order to promote the new portable to a public that had no exposure to transistors Raytheon gave away cards with a genuine dud transistor saying “Take this actual sample of an electronic miracle!” with an explanation of the benefits of transistors in the new set. The April '55 review of the Regency TR-1 found the $49.95 TR-1 to be a toy-like novelty which didn't come at a toy-like price, and stated that, "the consumer who has been waiting for transistor radios to appear would do well to await further developments before buying."The July '55 review of the Raytheon 8TP gave the set high marks: "The transistors in this set have not been used in an effort to build the smallest radio on the market, and good performance has not been sacrificed to attain this end." The 8TP series was ranked high in nearly all categories, "falling down only in sensitivity."” “The April and July 1955 issues of Consumer Reports separately put these two radios to the test, and concluded that Raytheon had every reason to call its 8TP the first serious transistor radio. Base width was controlled by monitoring electrical characteristics of the junctions as alloying proceeded. In 1956 George Freedman developed a method of controlling base width by starting with a wafer that included a PN junction and fusing an electrode containing a P impurity to an exposed N layer. (This geometry gives a stronger wafer than if the notches were cut parallel). Herman Nowak developed a method of obtaining alloy junction transistors with base width of only 1 mil by milling notches set at right angles on either side of the wafer and creating the base junction at the intersection of the notches. ![]() Raytheon research into improved RF performance focussed on methods to reliably reduce the base width of its transistors. ![]() Other than the above parameters, all the transistors in this range had identical specifications suggesting that they were made, tested and selected. The CK760 was adopted as a universal RF transistor and initially was used in all stages of the 8TP receiver in its first configuration. Notably the CK759 was not included in the initial release and may have been introduced later as a means of utilising low specification transistors that were usable as IF amplifiers. ![]()
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |