0
It's called back EMF or reverse EMF. The EMF is electro-motive force, or voltage. What is happening is that the original current flow creates a magnetic field. That field then induces a voltage that opposes the original voltage that is causing the current flow. This back EMF "resists" the original voltage's efforts to cause current flow. If the created magnetic field did not oppose the original "efforts" of the voltage source to make current flow, then it would aid that voltage to make current flow. We would then get something for nothing and perpetual motion would be possible. We can't do that.
What else can I help you with?
What is formed around a conductor when a current is passed through it?
A magnetic field.
What determines the strength of the magnetic field when current flows through a conductor?
Magnetic fields currently flows through a conductor is determined by multiplying the number of turns of wire by the current flow. This is what causes electricity.
Why transformer action can take place in DC and ac circuit?
First understand that every electrical conductor (wire) with current flow through it will produce an invisible magnetic field around it. This field is directly proportional to the magnitude of current flowing. Second (and inversely) realize that any conductor moving through a magnetic field will produce a voltage, And if provided with a complete circuit (a path to flow in) will result in current flow in that conductor. The movement can be from the conductor moving, or from the magnetic field moving, as long as there is 'relative motion' between the conductor and the magnetic field. In short, a conductor with current flow produces a magnetic field , a conductor and a magnetic field with relative motion between them produces current flow. (This is also the basis for how a motor works) AC means 'Alternating Current'! The current flow moves in one direction along a conductor, then reverses to zero and to equal magnitude in the opposite direction. Each time this current changes direction it produces a magnetic field, as it returns to zero the field collapses. As the current builds in the opposite direction the magnetic field builds again. In an AC transformer circuit, two conductors are placed in close proximity to each other and an alternating current is applied to the first conductor. This alternating current causes a magnetic field to build around the conductor, then collapse, build again in the opposite polarity and so on. This expanding and collapsing magnetic field creates relative motion between the field and the second conductor which then produces current flow of its own. This is called "transformer Action". In steady state DC circuits, the magnetic field is constant and there is normally no relative motion, therefore no "transformer action". There is however still a relative motion created when the circuit is first energized, and when it is de-energized. This collapsing field is how the ignition coil in your car works. In the simplest form, contacts (points) were opened by a cam, the open contacts de-energized the first conductor (the 12VDC primary). The resulting collapsing field cut across the secondary conductors. Because these conductors were wound into many turns or "coils" it actually multiplies the effect producing a high voltage in the secondary (connected to the ignition wires). This produced a voltage and current strong enough to jump across the gap of a spark plug. And, Yes Virginia, there is such a thing as a DC transformer.
What is the principle of motor action?
Motor runs by the principle of Michael Faraday's Electromagnetic Induction. It is defined as "when a current-carrying conductor is located in an external magnetic field perpendicular to the conductor, the conductor experiences a force perpendicular to itself and to the external magnetic field". The direction of rotation is determined by the Right-hand Rule and is "if the right thumb points in the direction of the current in the conductor and the fingers of the right hand point in the direction of the external magnetic field, then the force on the conductor is directed outward from the palm of the right hand".
What do you mean by eddy current loss?
Eddy currents are currents induced in conductors to oppose the change in flux that generated them. It is caused when a conductor is exposed to a changing magnetic field due to relative motion of the field source and conductor, or due to variations of the field with time. This can cause a circulating flow of electrons, or a current, within the body of the conductor. These circulating eddies of current create induced magnetic fields that oppose the change of the original magnetic field due to Lenz's law, causing repulsive or drag forces between the conductor and the magnet. The stronger the applied magnetic field, or the greater the electrical conductivity of the conductor, or the faster the field that the conductor is exposed to changes, then the greater the currents that are developed and the greater the opposing field.
What is the relationship between magnetic fields and electricity?
-- A current flowing through a conductor creates a magnetic field around the conductor. -- Moving a conductor through a constant magnetic field creates a current in the conductor. -- If there's a conductor sitting motionless in a magnetic field, a current flows in the conductor whenever the strength or direction of the magnetic field changes.
How electric current causes magnetic field around conductor?
When an electric current flows through a conductor, it creates a magnetic field around the conductor. This is due to the interaction between the moving charges (the electrons in the current) and the magnetic fields they produce. The magnetic field strength is directly proportional to the current flowing through the conductor.
How winding creates a magnetic field?
Current flow in any conductor creates a magnetic field, winding just concentrates it.
What is the magnetic effects of electrical current?
When an electrical current flows through a conductor, it creates a magnetic field around the conductor. This phenomenon is known as electromagnetism. The strength of the magnetic field is directly proportional to the current flowing through the conductor.
Creates a magnetic field?
When an electric current flows through a conductor, it creates a magnetic field around the conductor. This phenomenon is described by the right-hand rule, where the direction of the magnetic field is determined by the direction of the current flow. The strength of the magnetic field is directly proportional to the amount of current flowing through the conductor.
What happens when an electrical current runs through a conductor?
When an electrical current runs through a conductor, electrons flow in the direction of the current. This flow of electrons creates a magnetic field around the conductor. The amount of current flowing through the conductor is directly proportional to the strength of the magnetic field produced.
What is the key when using a magnet and a conductor to induce a current in the conductor?
Motion
How does electricity create magnetism?
When electric current flows through a conductor, it generates a magnetic field around the conductor. This is known as electromagnetism. The strength of the magnetic field is determined by the amount of current flowing through the conductor. This phenomenon is the basis for how electricity creates magnetism.
An electricity current is induced in a conductor to induce a current in the conductor?
An electric current can be induced in a conductor by moving it through a magnetic field or by changing the magnetic field around the conductor. This process is known as electromagnetic induction, and it is the principle behind how generators and transformers work. The changing magnetic field creates an electric field that causes electrons to move, generating an electric current in the conductor.
Does a change in magnetic field induce an electric current?
Yes, a change in magnetic field can induce an electric current in a conductor, as described by Faraday's law of electromagnetic induction. When a magnetic field through a conductor changes over time, it creates an electromotive force, which leads to the generation of an electric current in the conductor.
How can current be induced in a conductor?
Current can be induced in a conductor by changing the magnetic field around it. This change in magnetic field creates an electromotive force (EMF) within the conductor, which in turn causes the flow of current. This phenomenon is known as electromagnetic induction and is the basis for the operation of generators and transformers.
How electric current have magnetic effect?
When an electric current flows through a conductor, it creates a magnetic field around the conductor. This is due to the movement of charged particles, such as electrons, which generate a magnetic field. The strength of the magnetic field is directly proportional to the amount of current flowing through the conductor.
