On Wednesday, April 9, 2014 9:05:24 PM UTC-4, Phil Hobbs wrote:   
   > On 4/9/2014 9:00 PM, ggherold@gmail.com wrote:   
      
   >   
   > Bias tees are OK, but they don't protect the laser from ESD on the   
   > tuning input, and a transformer does.   
   >   
   ESD!   
   So way back when, we got started on the diode laser project.   
   The original prototype, (built by someone else) would blow out the LD (laser   
   diode).   
   (just by touching the case sometimes!)   
   I padded protection diodes all over the place*.  (As well as redoing the   
   current drive with the "correct" polarity to keep the case of the LD grounded.)   
   I then tested it by "sparking" everything with one of those piezo igniters   
   that you get in butane lighters.  Sparking with both polarities.   
   Since then we've never lost a diode. (that I know of)   
      
   George H.   
   (just in case some potential customer is reading at home.)   
   * Schottky in reverse, and several pn's in series in the forward direction.   
   these are at two places, at the electrical plug on the laser head   
   and then right where the LD plugs in.   
      
   >   
   > Cheers   
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   > Phil Hobbs   
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   > Dr Philip C D Hobbs   
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