1. What is the magnetic effect of current?

a. The magnetic effect of the current (the magnetic power generates the magnetic): Ost found that any wire with a current can generate a magnetic field around it, called the magnetic effect of the current.

b. Non -magnetic metals are current, but the magnetic field can be produced, and its effect is the same as the magnetic field established by the magnet.

2. The magnetic field generated around the long straight wire with current.

a. Around the long straight wire of the general current, there will be a magnetic field. The shape of the magnetic force line is a concentric circle that is closed with the wire of the wire, and the direction of the magnetic field is perpendicular to the direction of the current.

b. The Law of Ampere: The magnetic field established around the long straight wire with current, which is directly proportional to the size of the current on the wire, and is inversely proportional to the distance between the wires.

c. The direction of the magnetic field (or magnetic line): It can be determined by the right hand spiral.

2. current direction: hold the wire in the right hand, and the thumbs point to the direction of the current.

3. Magnetic field (or magnetic line) direction: the direction of four fingers.

4. Magnetic field generated by the streaming thread tube

a. The screw wire coil is equivalent to the magnetic field formed by the N poles of dozens of discscase -shaped thin magnets. It is like a magnetic field caused by a long cylindrical magnet.

b. The threaded coil with a current, the closer it is, that is to say, the turn in the unit length