What Is an AC Solenoid?

The energized solenoid is composed of an energized coil, and the magnetic induction wire outside the energized solenoid is sent from the north pole of the solenoid and returns to the south pole. However, the direction of the magnetic field inside the energized solenoid is from the south pole of the solenoid to the north pole.

Powered solenoid

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The amperage of linear current is also applicable to a short section of linear current. The ring current can be regarded as a plurality of small linear currents. For each small linear current, the direction of the magnetic induction intensity on the center axis of the ring current is determined by using the amperage of the linear current. The directions of the magnetic induction lines on the central axis of the ring current are obtained by superposition. The amperage of linear current is basic, the amperage of circular current can be derived from the amperage of linear current, and the amperage of linear current is the charge

Taking the current on the front of the solenoid as an example, the current is upward, the N pole is at the left end, the current is downward, and the N pole is at the right end. It is easy to remember and can be simplified as "upper left, bottom right".

For infinitely long straight dense turn solenoids

According to the Ampere Loop Theorem, the magnetic field outside the solenoid is almost 0, but only the magnetic field on the external axis is strictly 0.

Internal magnetic field is uniform magnetic field B = 0nI, n is the number of turns per unit length

To put it simply, the magnetic pole of an energized solenoid is only related to the direction of the current in the energized solenoid.

With the right-handed spiral rule, the battery is short, negative, and long, and the current flows from positive to negative. The four fingers of the right hand follow the direction of the current, and the direction of the thumb is the north pole of the solenoid. Outside the solenoid, the magnetic field lines go from north to south, and the small magnetic needles follow the magnetic field lines.