In 1956 Shockley returned to Palo Alto to found his own company. Later transistors were made from silicon, a much more common element and one that was protected from corrosion by a thin layer of silicon dioxide. Shockley’s design, the bipolar transistor, eliminated the delicate, troublesome point contacts. They also used the equivalent of cat’s whiskers, but two rather than one. Bardeen and Brattain used germanium instead of galena in that first transistor. Nevertheless, the principle upon which the crystal detector worked was the basis for the “point-contact” transistor. These early radios worked but only imperfectly. The radio user had to move the cat’s whisker around upon the germanium crystal to find a suitable point of contact where a radio signal could be picked up. The early radios had signal detectors which consisted of a fine wire, called a cat’s whisker, impinging upon a galena (lead sulfide) crystal. There was precedent for this type of device. Shockley had started working in 1936 on the solid-state physics theory that was the basis for the transistor. When he completed his doctorate, specializing in quantum physics, he went to work for Bell Labs. William Shockley was raised in Palo Alto and did his undergraduate work at the California Institute of Technology (Cal Tech) in Pasadena and went on for his Ph.D. Thus the transistor was, in large part, Shockley’s creation. Shockley subsequently designed a new type of transistor called the “bipolar” transistor which was superior to the point-contact type and replaced it. What Bardeen and Brattain had created was the “point-contact” transistor. Shockley, as their supervisor, shared in the glory. Bardeen and Brattain were called in to handle the engineering and development, which they did in the relatively short time of two years, to the consternation of Shockley. While he could work out the theory successfully but after eight years of trying he could not build a working model.
Shockley had been working on the theory of such a device for more than ten years. William Shockley played a quite different role in the invention than the other two. The three individuals credited with the invention of the transistor were William Shockley, John Bardeen, and Walter Brattain. William Shockley, John Bardeen, and Walter Brattain. Bell Labs is the research arm of the American Telephone and Telegraph (AT&T). Since the US demand for such is small, many of these mfr's don't officially support the parts in the US, so you have to get them from overseas sources or some of the gray market vendors, some of whom are quite reputable and wholly legal.The transistor was successfully demonstrated on Decemat Bell Laboratories in Murray Hill, New Jersey. But for critical audio apps it's best to go hunt down the original manufacturer's parts. There are plenty made that are good enough for their applications most of the time. The sad fact is that, with the exception of some small firms, there are not that many competitively high quality low-freq discrete semis made by US or European manufacturers anymore. Soundcraft is not being disingenuous when they can't give you those "generic equivalent ". There are plenty of Japanese parts made and packaged in other countries though, under their close supervision, and they are generally of excellent quality.
But caveat emptor has always been good advice. There really isn't a whole lot of that for semiconductors-and you are not likely to be approached by one of the fences for the stolen IC's that get pinched from time to time anyway. The transistor tester probably is set up for a different pinout than the parts.Ĭhinese black market-hmmm.
for some reason it won't detect these transistors, not sure why. Of course, they wanted me to buy from them at 4 times the cost.Īnother funny thing is I have this transistor tester ( BK precision 510 ) that usually tells me that its either a NPN or PNP. Soundcraft support would not give me a cross reference to another generic part number equivilent. ( NO CHINESE BLACK MARKET STUFF EITHER) ORIG # printed on Transistor. I'm looking for a fairchild, motorola, STmicro, etc. I have checked the usual online cross reference resources, but there may be others I have not discovered yet Transistors I'm having trouble cross referencing to something else. This is out of a Soundcraft Spirit Studio Console 24x8
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