From: jjk439@gmail.com   
      
   On Tuesday, October 22, 2013 10:50:17 AM UTC-4, JW wrote:   
   > On Tue, 22 Oct 2013 05:59:52 -0700 (PDT) jjk wrote in   
   >    
   > Message id: <43fdc3c0-c590-48a8-8f94-66253b34100e@googlegroups.com>:   
   >    
   >    
   >    
   > >Thanks to all who replied.   
   >    
   > >There is definitely very wrong. I just took delivery of 50 Fairchild   
   replacement zeners and reran my tests to verify, this time using a 330 ohm   
   resistor. The results are below for both 3.3v and 5.6v parts. The 5.6v part   
   works as expected and doesn't    
   conduct until the avalanche voltage is approached whereas the 3.3v part is   
   still exhibiting the wrong behavior. I had to raise vcc to 25v to see 3.3v at   
   the cathode, then the magic smoke came out of the resistor. :)   
   >    
   > >   
   >    
   > >vcc -> 330 ohm resistor -> milliamp meter -> zener cathode, zener anode to   
   ground.   
   >    
   > >330 ohm resistor measures 327 ohms   
   >    
   > >   
   >    
   > >1N4728A 3.3v 1W Zener diode   
   >    
   > >   
   >    
   > >        Iz   
   >    
   > >vcc     (mA)    Vzener   
   >    
   > >1.5     0.2     1.42   
   >    
   > >2.0     0.8     1.72   
   >    
   > >2.5     1.7     1.91   
   >    
   > >3.0     2.8     2.05   
   >    
   > >3.5     4.1     2.16   
   >    
   > >4.0     5.3     2.24   
   >    
   > >4.5     6.6     2.3   
   >    
   > >5.0     8.0     2.37   
   >    
   > >5.5     9.4     2.43   
   >    
   > >6.0     10.8    2.48   
   >    
   > >7.0     13.6    2.56   
   >    
   > >8.0     16.5    2.62   
   >    
   > >9.0     19.4    2.69   
   >    
   > >10.0    22.4    2.73   
   >    
   > >20.0    55.2    3.1   
   >    
   > >25.0    71.3    3.3   
   >    
   >    
   >    
   > Where are you getting these diodes?   
      
   I received a package of 50 Fairchild devices from Jameco.com.    
   Then I purchased 5 NTE devices from a local electronics store.   
   All of the ones I have tested from the above failed.   
   I contacted Jameco and they sent 50 replacements and all that I tested failed   
   in the same way. I've been in contact with the Jameco technical rep and they   
   are looking into this and trying to obtain devices from another lot from their   
   supplier.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)