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Ian Bell
12/29/05 14:47
Read: 645 times
United Kingdom

#106201 - Germanium and Silicon
Responding to: Kai Klaas's previous message
Kai Klaas said:
This quiz was given 1987. Do you really think that the use of Germanium diodes is assumed? If it shall refer to DTL, implemented on same chip, then, if a silicon transistor is used, also silicon diodes are to be expected.

AFAIR Texas introduced the 74 series TTL in 1974 and that was definitely silicon. For the next ten years at least, Fairchild still made DTL germanium devices.

So in 1987 when this exam was set silicon was the norm and germanium rarely used. So to that extent I agree it is hard to see how germanium is assumed.

However, many of these schools are well known for teaching an almost identical syllabus for many years, so I would not be surprised if part of it went back to the days of descrete logic made from individual transistors and diodes. I know for a fact that there were many circuits just like this in use when I started in the UK Aerospace industry in 1969. I have seen this very cicuit used in a lesson on logic.

So yes, experience tells me thet are germanium diodes.


List of 32 messages in thread
CET Exam Chaper 9 Questions        Charles Bannister      12/24/05 15:30      
   Answers      Steve M. Taylor      12/24/05 15:50      
      Answers provide later by myself.      Charles Bannister      12/24/05 16:02      
         See Q5      Steve M. Taylor      12/24/05 16:09      
         Vintage?????      Ian Bell      12/28/05 09:58      
            No signs of senility      Steve M. Taylor      12/28/05 10:38      
               Ah, well      Ian Bell      12/28/05 12:22      
                  An achievement      Steve M. Taylor      12/28/05 12:36      
   Q3      J. Guy      12/28/05 10:11      
      yes      Erik Malund      12/28/05 10:27      
      Depends      Ian Bell      12/28/05 12:26      
         If Q3 did not have a clear answer, neith      Erik Malund      12/28/05 12:32      
         What a messy circuit...      Kai Klaas      12/28/05 19:57      
            Tough      Steve M. Taylor      12/29/05 04:31      
            assume the stupidity of the test maker      Erik Malund      12/29/05 06:47      
               Changes nothing      Kai Klaas      12/29/05 09:07      
                  germanium diodes silicon transistors or      Erik Malund      12/29/05 09:26      
                     Nice link!      Kai Klaas      12/29/05 09:36      
                        I googled      Erik Malund      12/29/05 10:28      
            Germanium and Silicon      Ian Bell      12/29/05 14:47      
               in my first job the ICs were PCBs using      Erik Malund      12/29/05 15:00      
                  DTL      J. Guy      12/29/05 15:15      
                     Appeal ?      Steve M. Taylor      12/29/05 16:25      
               cet test      Terry Lingle      12/29/05 21:41      
               From a contemporary source...      Andy Neil      12/30/05 04:12      
                  Top Marks      Steve M. Taylor      12/30/05 06:28      
                     To Charles!      Andy Neil      12/30/05 06:31      
   ANSWERS      Charles Bannister      01/05/06 18:00      
      Conclusion      Kai Klaas      01/06/06 05:25      
         Germanium diodes are      Terry Lingle      01/06/06 06:43      
            silly concept      Erik Malund      01/06/06 07:12      
               yes      Terry Lingle      01/06/06 08:37      

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