I have made an electromagnet using copper coil of 1.0 mm diameter, iron core of 2 cm dia & 8 cm length for my project. Supplied voltage is 12 VDC and current it consumes is 9.0 Amp. It has 1.5 Ohm resistance. I want to change the polarity of electromagnet like pulsing. I have to control e-magnet pulsing through arduino uno.

I learned H-Bridge is a way to do it. What h-bridge should i use for this amount of current and voltage? What precautions should i take when connecting the H-Bridge to arduino if any? Any other things related to doing changing polarity of e-magnet if pointed out will be of great help for me.

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    \$\begingroup\$ From memory of your previous questions, you need a big dc content and a smaller ac content superimposed to give you the result you want. Has this changed? If not I would suggest not using a H bridge but, you need to concur. \$\endgroup\$ – Andy aka Jan 21 '14 at 14:38
  • \$\begingroup\$ Everything is same since your last answer. So far I have made powerful enough dc operated e-magnet to be useful for my project. Now I figured out after experiment with it that it will work fine for me if its polarity is reversed. And I find H-Bridge an ic equipment used for that,for my delight as I don't have to make such thing like in the case of e-magnet. This is whole situation. I have e-magnet with specifications I put in OP, I have to change its polarity with frequency of somewhat like Morse code. \$\endgroup\$ – enterprize Jan 22 '14 at 9:54

Firstly, do you need to alternate the polarity rapidly? Rapid switching of 9A through an inductive load such as an electromagnet requires some care.

If not, the easiest solution is probably to use a pre-built H-bridge driver module designed for a single DC brushed motor, such as this one, which has as a 5V interface suitable for an Arduino. Similar things (often less well designed/documented) are available cheaply on ebay.

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  • \$\begingroup\$ The frequency of alternation is going to be very nearly like of Morsecode. May be little more time added between successive turns. \$\endgroup\$ – enterprize Jan 22 '14 at 9:57
  • \$\begingroup\$ are not there IC H-Bridge available for this current requirements? Such like this electronics.divinechildhighschool.org/Home/Arduino-Lessons/… \$\endgroup\$ – enterprize Jan 22 '14 at 19:51
  • \$\begingroup\$ I don't know of any. 9 amps continuous current is a lot for a monolithic IC. \$\endgroup\$ – Chris Johnson Jan 22 '14 at 22:54
  • \$\begingroup\$ thank you, I ordered your mentioned & few others from e-bay. Once I get & start experiment, will share result. \$\endgroup\$ – enterprize Jan 23 '14 at 11:43

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