How is the relationship between self inducted electromotive force and current in the coil calculated

According to the conclusion of the experiment: at the moment of power failure, the current in the self-inductance coil always disappears from the original current, then the maximum self-induced electromotive force should be equal to the original current multiplied by the load, that is, the larger the load, the greater the self-induced electromotive force will be. From the self-induced electromotive force e=l*δi δt, it can be seen that the faster the current changes, the faster the energy loss.

According to the conservation of energy, the coil can store so much magnetic field energy when the original current is large, if the power is off, the larger the load, then the self-induced electromotive force is larger, but the faster the energy is dissipated; The smaller the load, the smaller the self-induced EMF, but the slower the energy dissipation.

Because the current in the coil reflects the "inertia of electricity", I insist that the view that "the current in the coil always disappears from the original value" is correct, and then use Ohm's law and energy conservation to reason

The final conclusion should be that when the power is off, the current in the coil always starts to disappear from its original value. The magnitude of the induced electromotive force is related to the size of the load: the larger the load, the greater the induced electromotive force, but the energy is dissipated quickly; The smaller the load, the smaller the induced EMF, but the energy dissipation is slow.

If you agree with my reasoning point of view,. If you don't agree, please question it and discuss it together to reach the right conclusion.

The strength of the electric field due to the change of the magnetic field is related to the speed of change of the magnetic field, that is, the rate of change of the magnetic field b t, so the greater the rate of change of the magnetic field, the stronger the electric field generated, and the stronger and greater the energy of the electric field. If the change of the magnetic field is uniform, then the rate of change of the magnetic field b t is a constant quantity, and the electric field generated by it is also a constant electric field, that is, the field strength e everywhere in the electric field is constant, if the magnetic field is not uniformly changed, b t is a variable, and the electric field generated by it is also a changing electric field, that is, e is changing. If e is a magnetic field that varies in magnitude and direction by sinusoid, the electric field resulting from it is an electric field that varies in magnitude and direction by sinusoid.

By But generally l does not change with t, get.

The size of the self-induction electromotive force (emf by self-induction) el:

The direction of EL: Judgment method, 1) take the positive direction of the loop L road, 2) judge the positive or negative of I, 3) judge the positive or negative of Di, 4) judge the positive or negative of EL (e.g. EL > 0, then EL is along the direction of L road).

The role of EL is to stop the change in electrical current.

l The role in the circuit: resisting AC; DC.

As long as there is an electric current flowing through the coil, a self-induced electromotive force is generated. Zheng Zhe ().

a.That's right. b.Mistake.

Which god is sure to answer: Li Cong loses a

When the current in the coil changes, a self-induced electromotive force is generated at both ends of the coil.

When the current in the coil changes, a magnetic field is created that travels through the space inside and around the coil. Since the change in magnetic flux over time causes the induction of the electric field, a self-induced electromotive force is generated at both ends of the ** circle. This is described by Faraday's law of electromagnetic induction.

It states that when a magnetic flux passes through a closed loop, an induced electromotive force is generated in that loop.

The coil is the inductance, and if its self-inductance coefficient is l, then the self-inductance electromotive force when the current changes can be calculated by the following formula:

The formula for self-induced electromotive force: e = l i t. From the law of electromagnetic induction, it can be seen that the magnitude of the self-induced electromotive force is positive to the rate of change of the current in the coil.

The characteristics of self-induced electromotive force are:

1. The direction of self-induced electromotive force: self-induced electromotive force always hinders the change of the original current in the conductor. When the current increases, the self-induced electromotive force is opposite to the original current direction; When the current decreases, the self-induced electromotive force is in the same direction as the original current.

Brother shouts "obstruction" is not "blocking", "obstruction" is actually "delaying", so that the original current in the circuit changes more slowly.

2. The magnitude of self-induced electromotive force: it is determined by the conductor itself and the degree of change of the current through the conductor. In a constant-current circuit, self-inductance occurs only at the moment when the power is turned on and off.

3. From the law of electromagnetic induction, the self-induced electromotive force can be obtained, and the magnitude of the self-induced electromotive force is proportional to the rate of change of the current in the coil. When the current in the coil changes by 1 A within 1 s, the self-inductance electromotive force caused by the coil is 1 V, and the self-inductance coefficient of the coil is 1 h.

Correct Answer: Hinders the change of the original current inside the coil.

The magnitude of the self-induced electromotive force is proportional to the current change rate of the coil, and it is right that the self-induced electromotive force is the induced electromotive force generated in the self-inductive phenomenon.

The magnitude of self-induced electromotive force: determined by the conductor itself and the degree of change of the current through the conductor In a constant current circuit, the self-inductance phenomenon occurs only at the moment of power on and off

Direction of self-induced electromotive force: Self-induced electromotive force always hinders the change of the original current in the conductor When the current increases, the self-induced electromotive force is opposite to the direction of the original current; When the current decreases, the direction of the self-induced electromotive force is the same as the direction of the original current

According to the law of electromagnetic induction, the magnitude of the self-induced electromotive force is proportional to the rate of change of the current in the coil.

Self-induced electromotive force e self=-n*δ δt = lδi δt where l: self-inductance coefficient (h) (coil l with iron core is larger than without iron core), δi: change current, t: time spent, i δt: self-inductance current change rate (speed of change).

Equation E from nδ δt lδi δt{l: self-inductance coefficient (h) (coil l is larger with iron core than without iron core), δi: change current, δt: time spent, δi δt: rate of change of self-inductance current (speed of change)}

Magnetic flux phi=n*l*i (n is the number of turns).

Induced electromotive force v=dphi dt

i.e. v=n*l*di dt, so the induced electromotive force is proportional to the rate of change of the current.

When the current decreases, the self-inductive electromotive force can only hinder the current from decreasing, but cannot prevent the current from decreasing, that is to say, the current will still decrease, but the rate of reduction will be slower and the time will be longer, so the current in the self-inductance coil must be less than the original current;

The turns of the self-inductive coil are connected in series with each other, and the total electromotive force is equal to the sum of the electromotive forces of each turn.

For the self-inductance coil, even if the current change is slow, the self-induced electromotive force generated by each turn of the coil is small, if the number of turns of the self-inductance coil is enough, the self-inductance electromotive force of each turn is added up, and the total self-induced electromotive force can also be large, which may be greater than the original power supply electromotive force.

Wrong. Copy.

The direction of the self-induced electromotive force always has to block the original.

Change in current. That is to say, when the zhi current increases, the direction of the self-induced electronically charged DAO potential is inconsistent with the direction of the current, which plays the role of hindering the current. When the current decreases, the direction of the self-induced electromotive force is consistent with the direction of the current, which plays the role of pushing the current.

Note that the direction of the electromotive force, or voltage and current, should not be called "same, not the same" but "consistent, inconsistent").

The characteristics of the inductor make it impossible for the current of the inductor to change abruptly.

When the power is off, the current in the loop suddenly drops to 0, but due to the existence of inductance, at the moment of power failure, its current will not become smaller, and the blind is equipped to maintain the current on the original coil branch.

Then, as the branch loses power, the current is supplied by the inductor.

This current is in the same direction as the original current, but gradually decays and decreases.