From: dhky@shaw.ca   
      
   On 04/09/2013 2:30 PM, Salmon Egg wrote:   
   > In article ,   
   >   "Paul Hovnanian P.E."  wrote:   
   >   
   >> Patrick Chung wrote:   
   >>   
   >>> Inductor current can't be suddenly cutoff  if no freewheel diode is   
   >>> attached. New tutorial is ready   
   >>   
   >> Just to be pedantic: Inductor current can't be suddenly cut off even with a   
   >> freewheel diode. The purpose of the diode is to give a decaying inductor   
   >> current a path when the driving source is suddenly cut off.   
   >   
   > It is more than that. Free wheeling rectifier combinations such as   
   > bridges, allow more efficient charging of capacitors by efficiency while   
   > the capacitor has almost no charge. Diodes still dissipate some power.   
   > Remember, repetitive charging and discharge from a non-inductive dc   
   > source delivers V*I/2 while drawing power V*I. V is peak capacitor   
   > voltage while I is the average (dc) current.   
   >   
   > My sarcastic point is that sudden changes in current in a conductor   
   > gives large voltages should be learned very early by anyone working with   
   > electrical circuits. I found that out early in life using dry cells and   
   > my mother's motorized mixer.   
   >   
   I also learned  that by fooling around with a 6V  dry cell and an old   
   Ford ignition coil (the kind in a nice wooden box- ). It takes skill (or   
     ignorance) to hold a wire in each hand and energize the primary but   
   still get said hands across the secondary.   
      
      
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   Don Kelly   
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