Explain the concept of electrical magnetic hysteresis.
1 Answer
Electromagnetic hysteresis, also known as magnetic hysteresis, is a phenomenon that occurs in ferromagnetic materials when they are subjected to varying magnetic fields. It describes the lagging of the magnetic induction (B) behind the applied magnetic field intensity (H) during the process of magnetization and demagnetization. This lag results in a characteristic loop-shaped graph known as the hysteresis loop.
Here's a step-by-step explanation of the concept of electromagnetic hysteresis:
Ferromagnetic Materials: Ferromagnetic materials are substances that have a strong affinity for magnetic fields. When exposed to an external magnetic field, the domains (small regions with aligned magnetic moments) within these materials tend to align themselves with the applied field, creating a net macroscopic magnetic moment in the material.
Magnetization: When an external magnetic field (H) is applied to a ferromagnetic material, the magnetic domains within the material align themselves with the field, causing an increase in the magnetic induction (B) in the material. This increase in B is a response to the applied H and is known as magnetization.
Saturation: As the applied magnetic field (H) increases, the magnetic induction (B) also increases until it reaches a maximum value where all the magnetic domains are fully aligned. At this point, the material is said to be saturated, and further increases in the applied field do not cause significant changes in the magnetic induction.
Demagnetization: If the external magnetic field (H) is gradually reduced back to zero, the magnetic induction (B) does not decrease linearly. Instead, it follows a different path, and the material retains some residual magnetization. This retention of magnetization even after the external field is removed is known as remanence.
Coercivity: To completely demagnetize the material, an opposing magnetic field needs to be applied to reverse the magnetization to zero. The intensity of the opposing field required to bring B back to zero is known as the coercive force (Hc). Different ferromagnetic materials have different coercivities.
Hysteresis Loop: When the magnetization process is plotted as a graph of magnetic induction (B) against magnetic field intensity (H), a closed loop is obtained, known as the hysteresis loop. The shape of the loop depends on the material's properties, particularly its coercivity and permeability.
The hysteresis loop visually illustrates the lagging effect of magnetic induction (B) with respect to the applied magnetic field (H) during the process of magnetization and demagnetization. The area enclosed by the loop represents the energy lost as heat during each cycle of magnetization and demagnetization and is proportional to the magnetic hysteresis losses in the material.
Electromagnetic hysteresis is an essential phenomenon in various applications, such as transformers, electric motors, and magnetic storage devices like hard drives. Engineers and scientists consider hysteresis effects when designing and optimizing magnetic systems to minimize energy losses and improve device efficiency.
Here's a step-by-step explanation of the concept of electromagnetic hysteresis:
Ferromagnetic Materials: Ferromagnetic materials are substances that have a strong affinity for magnetic fields. When exposed to an external magnetic field, the domains (small regions with aligned magnetic moments) within these materials tend to align themselves with the applied field, creating a net macroscopic magnetic moment in the material.
Magnetization: When an external magnetic field (H) is applied to a ferromagnetic material, the magnetic domains within the material align themselves with the field, causing an increase in the magnetic induction (B) in the material. This increase in B is a response to the applied H and is known as magnetization.
Saturation: As the applied magnetic field (H) increases, the magnetic induction (B) also increases until it reaches a maximum value where all the magnetic domains are fully aligned. At this point, the material is said to be saturated, and further increases in the applied field do not cause significant changes in the magnetic induction.
Demagnetization: If the external magnetic field (H) is gradually reduced back to zero, the magnetic induction (B) does not decrease linearly. Instead, it follows a different path, and the material retains some residual magnetization. This retention of magnetization even after the external field is removed is known as remanence.
Coercivity: To completely demagnetize the material, an opposing magnetic field needs to be applied to reverse the magnetization to zero. The intensity of the opposing field required to bring B back to zero is known as the coercive force (Hc). Different ferromagnetic materials have different coercivities.
Hysteresis Loop: When the magnetization process is plotted as a graph of magnetic induction (B) against magnetic field intensity (H), a closed loop is obtained, known as the hysteresis loop. The shape of the loop depends on the material's properties, particularly its coercivity and permeability.
The hysteresis loop visually illustrates the lagging effect of magnetic induction (B) with respect to the applied magnetic field (H) during the process of magnetization and demagnetization. The area enclosed by the loop represents the energy lost as heat during each cycle of magnetization and demagnetization and is proportional to the magnetic hysteresis losses in the material.
Electromagnetic hysteresis is an essential phenomenon in various applications, such as transformers, electric motors, and magnetic storage devices like hard drives. Engineers and scientists consider hysteresis effects when designing and optimizing magnetic systems to minimize energy losses and improve device efficiency.