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Oliver Sedlacek
04/03/12 05:02
Read: 568 times

#186982 - Catch diode
Responding to: Muhammad Naeem's previous message
If you have an inductive load like a solenoid it stores energy in it's magnetic field. When your driver switches off, the stored energy needs to go somewhere and the voltage at the coil terminal rises until it does go somewhere. A correctly connected catch diode is a common solution as it clamps the voltage to the supply and returns the stored coil energy to the supply. As the diode 'catches' the stored energy, it is often called a catch diode.

Other solutions are possible, so you don't need the diode if you do something else with the energy. It is possible to use the drive transistor to dump the energy by turning it on a a bit when the coil terminal voltage is very high.

If you don't do anything the high voltage spike will probably exceed the drive transistor voltage rating and blow it up, either quickly or slowly.

List of 13 messages in thread
Protection diode      Muhammad Naeem      04/03/12 03:33      
   Catch diode      Oliver Sedlacek      04/03/12 05:02      
      PCB design is correct      Muhammad Naeem      04/03/12 05:11      
         Diode connection      Per Westermark      04/03/12 07:11      
   Can work...      Kai Klaas      04/03/12 06:54      
      can is a big word      Erik Malund      04/03/12 07:06      
         And resistors      Per Westermark      04/03/12 07:14      
         Can, will ...      Kai Klaas      04/03/12 07:48      
            probabl;y, but      Erik Malund      04/03/12 07:52      
               Definitely room for improvements      Per Westermark      04/03/12 15:28      
                  for our non-fluent friends      Erik Malund      04/04/12 07:23      
                     Yes - diodes as close to inductors as possible      Per Westermark      04/04/12 09:03      
   la cucaracha      Erik Malund      04/03/12 07:49      

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