What is a magnetic amplifier (magamp)?
1 Answer
A magnetic amplifier (magamp), also known as a saturable reactor or magnetic controlled reactor, is an electronic device that uses magnetic cores to amplify electrical signals. It belongs to the family of nonlinear magnetic devices and was widely used in the early to mid-20th century as a type of electronic amplifier and control element in various applications.
The basic principle of a magnetic amplifier revolves around the magnetic properties of its core material, typically made of ferromagnetic material such as iron. When a direct current (DC) is passed through the primary winding of the magnetic amplifier, the core becomes magnetized. As the magnetic flux in the core increases, the core moves closer to saturation—the point where further increase in magnetic flux doesn't result in a significant increase in the core's magnetization.
The important characteristic of magnetic amplifiers is their nonlinearity in the magnetization curve. When a varying input signal (AC or modulated DC) is superimposed on the DC bias current in the primary winding, the core's magnetization varies non-linearly, causing changes in the inductance of the device. This, in turn, affects the impedance seen by the secondary winding, allowing the signal to be amplified or controlled.
Magnetic amplifiers were widely used in power control applications and voltage regulation before solid-state electronics became prevalent. They were employed in areas like power supplies, motor control, and telecommunications. However, their usage declined with the advent of more efficient and reliable solid-state devices like transistors and integrated circuits, which offered superior performance, smaller size, and reduced power consumption.
While magnetic amplifiers are no longer as common in modern electronics, the principles they embody have contributed to the development of other magnetic devices and power control methods, which continue to be used in specialized applications.
The basic principle of a magnetic amplifier revolves around the magnetic properties of its core material, typically made of ferromagnetic material such as iron. When a direct current (DC) is passed through the primary winding of the magnetic amplifier, the core becomes magnetized. As the magnetic flux in the core increases, the core moves closer to saturation—the point where further increase in magnetic flux doesn't result in a significant increase in the core's magnetization.
The important characteristic of magnetic amplifiers is their nonlinearity in the magnetization curve. When a varying input signal (AC or modulated DC) is superimposed on the DC bias current in the primary winding, the core's magnetization varies non-linearly, causing changes in the inductance of the device. This, in turn, affects the impedance seen by the secondary winding, allowing the signal to be amplified or controlled.
Magnetic amplifiers were widely used in power control applications and voltage regulation before solid-state electronics became prevalent. They were employed in areas like power supplies, motor control, and telecommunications. However, their usage declined with the advent of more efficient and reliable solid-state devices like transistors and integrated circuits, which offered superior performance, smaller size, and reduced power consumption.
While magnetic amplifiers are no longer as common in modern electronics, the principles they embody have contributed to the development of other magnetic devices and power control methods, which continue to be used in specialized applications.