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The electromagnet (polarity) is determined by the direction of current.
the direction of the flow of current
Neodymium Iron Boron (NdFeB or NIB) would be the stongest material of an magnet.(Is the tempature which for this material is 12,800 . Hc is the lenth of the material which is 12,300. BHmax is the strenth which is for this material 40 . The other strenth for other materials are 26, 5.5,3.5 . The highest was 40
The field strength of an electromagnet (and the shape of that field) will largely be determined by the physical characteristics and geometry of the coil (wire size, number of turns, spacing of turns, diameter of coil, etc.), the current flow through the coil's wire and the material and shape of the core. The most variable aspect of the electromagnet is the current we run through it. Once the electromagnet is designed and constructed, the limits are "built in" and about all we can vary is current. Use the link to the GSU Hyperphysics site and it's diagram of an electromagnet. (Be sure to scroll down a bit.) Also, look around on that site, if you have time. There is a lot of good basic physics there. The explanations are very reader friendly and the diagrams are pretty good, too.
Welder polarity has to do with DC (Direct Current) welders. Essentially, polarity is the direction of the current. Straight polarity means that the current is running from the electrode, to the metal, and back through the grounding clamp. Reverse polarity means that the current is going the opposite way, from the grounding clamp, through the metal, and up through the electrode.
The electromagnet (polarity) is determined by the direction of current.
the direction of the flow of current
The polarity of the electromagnet reverses.
Resistors have no polarity. The voltage across a resistor is determined by the direction of current flowing through that resistor (and vice versa).
Nothing - The polarity of an electromagnet depends on the direction of current flow and you can effect the same change in orientation to the earth's field by moving the electromagnet rather than the earth's field.
Current flow is from positive to negative. Use the left hand rule for finding the north and south poles. Grab the coil in your left hand, with your fingers wrapped around the coil in the direction of the current flow. Your thumb will then point toward the north pole of the coil. Reverse the positive - negative connections to the coil and the north - south poles will change ends. The left hand rule will still be in effect as the current will now be flowing in the reverse direction as it was in the first connection.
Current flow is from positive to negative. Use the left hand rule for finding the north and south poles. Grab the coil in your left hand, with your fingers wrapped around the coil in the direction of the current flow. Your thumb will then point toward the north pole of the coil. Reverse the positive - negative connections to the coil and the north - south poles will change ends. The left hand rule will still be in effect as the current will now be flowing in the reverse direction as it was in the first connection.
Neodymium Iron Boron (NdFeB or NIB) would be the stongest material of an magnet.(Is the tempature which for this material is 12,800 . Hc is the lenth of the material which is 12,300. BHmax is the strenth which is for this material 40 . The other strenth for other materials are 26, 5.5,3.5 . The highest was 40
Polarity
Yes, a diode inherently has polarity, as current is only allowed to flow one direction.
The field strength of an electromagnet (and the shape of that field) will largely be determined by the physical characteristics and geometry of the coil (wire size, number of turns, spacing of turns, diameter of coil, etc.), the current flow through the coil's wire and the material and shape of the core. The most variable aspect of the electromagnet is the current we run through it. Once the electromagnet is designed and constructed, the limits are "built in" and about all we can vary is current. Use the link to the GSU Hyperphysics site and it's diagram of an electromagnet. (Be sure to scroll down a bit.) Also, look around on that site, if you have time. There is a lot of good basic physics there. The explanations are very reader friendly and the diagrams are pretty good, too.
The magnetic field reverses direction.