H-bridge and electromagnets

[roboSonny]

i want to make an electromagnet that i can control it via my controller(changing the electromagnetic field) with commands.I think that i can do it with an h-bridge...am i right?if i am,what type of h-bridge should i use?if not,whats your opinion?

[waltr]

You could use an H-bridge but I don't think you would need to reverse the polarity of the magnetic field (reversing the voltage to the coil).

A simpler method is just a transistor (bi-polar of MOSFET) the drive the coil from a processor pin.
Either the transistor or H-bridge requirements would be to handle the voltage and current needed.

[roboSonny]

i thing the h-bridge would be the right option for me as i want to diverse the polarity.what type of h-bridge should i use though?what precautions should i take when connecting the electromagnet to my controller in order to prevent burning the controller? thanx for  your help!

[waltr]

H-bridge requirements would be to handle the voltage and current needed.

[Soeren]

Hi,

i thing the h-bridge would be the right option for me as i want to diverse the polarity. [...]

An H-bridge will be a waste of 3 transistors, unless you want to use a permanent magnet as the core. A regular electromagnet with an iron core will attract magnetizable material no matter its polarity.

what type of h-bridge should i use though?

You shouldn't, but anyway, there is only one type of H-bridge - the one where 4 transistors and the load is arranged to look like the letter "H" in a schematic.

what precautions should i take when connecting the electromagnet to my controller in order to prevent burning the controller?

Just use a transistor to separate and a fly-back diode directly over the coil terminals to kill the inductive kick from the coil (to keep the transistor alive).