Working with solenoids

Discussion in 'Embedded Systems and Microcontrollers' started by prabhubng, Feb 21, 2013.

  1. prabhubng

    Thread Starter New Member

    Sep 29, 2009
    6
    0
    Hi,

    I am working with an arduino to control a solenoid made by me, I understand that a diode across the coil will protect it from reverse flow of current, but in my scenario I am trying to switch the power using an H Bridge to reverse the polarity in this case I am not sure how to connect the diode correctly or is there any other was I can handle this problem?

    Can someone give me idea on this?

    Thanks in advance
    -Prabhu
     
  2. MrChips

    Moderator

    Oct 2, 2009
    12,421
    3,357
    Obviously, you cannot put the diode across the coil. The diode is used to protect the semiconductor switches not the coil. Put it across these.
     
  3. praondevou

    AAC Fanatic!

    Jul 9, 2011
    2,936
    488
    If you use a H-bridge with MOSFETs you generally don't need the diode. They already have an intrinsic body diode built in.

    The voltage over the load is clamped to the power supply voltage of the H-bridge.

    You can however add four diodes to your H-bridge, one on each MOSFET drain-source. (pointing to + of course)

    An IGBT doesn't have a body diode, unless it is built in on purpose.

    You would also need those diodes for an H-bridge with biploar transistors.
     
  4. John P

    AAC Fanatic!

    Oct 14, 2008
    1,632
    224
    Generally a solenoid will work the same regardless of which way the current flows. Is this a type with a permanent magnet moving in it, like a voice coil?
     
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