What is a Magnetron?
A magnetron consists of a plate of the material of which all or part of the coating is to consist (referred to as the target) with magnets arranged behind it with alternating polarity. See below. Schematic of a magnetron The Magnetron – How is it used to coat tools and components? When power is supplied to the magnetron a negative voltage of typically -300V or more is applied to the target. This attracts argon ions to the target surface at speed. When they collide with the surface two important processes take place. Firstly atoms are knocked out of the target surface with mean kinetic energies of 4 to 6 eV- this is sputtering. To learn more about sputtering click the link. Secondly secondary electrons are emitted from the target surface that become trapped by the magnetic fields and undergo further ionizing collisions sustaining the plasma. Also during the sputtering process a glow is observed as can be seen below, this is caused by excited ions relaxing to a lower energy state and emi
Typically used in microwave ovens, a magnetron is a tube that utilizes electrical and magnetic currents in order to create an intense heat output. The electromagnetic energy created from a magnetron can travel at the speed of light and is the same type of energy used in radio and television broadcasting. A magnetron tube has a filament in the center which heats up when it is exposed to a slight amount of voltage or energy. The filament gives off electrons as it becomes hotter. These electrons move outward in search of positive anodes, or electrodes, but they come in contact with a magnetic field along the way. The magnetic field within the magnetron repels the electrons. As a result, they become stuck in one area and begin rotating in circles. This creates more heat, as well as a supply of energy strong and hot enough to quickly cook an item. In the 1920s, a General Electric employee, Albert Hull, was researching vacuum tubes when he created the magnetron. However, Hull could think of
The magnetron is a device inside of the microwave oven which produces the electromagnetic waves that cook or heat the food. This device is usually located near the microwave light in several microwave models. Many parts make up the magnetron, but the most important ones are: the diode vacuum tube which is a semi conductor allowing the flow of current in one direction only and having two terminals. The vacuum tube is a tube with no air. the cathode and coaxial anode. The anode is the positive electrode in an electronic device while the cathode is the negative electrode in an electronic device. Coaxial means that two concentric (having a common center) are conductors separated by an insulator. Click to see images of a magnetron Image 1 Image 2 Image 3 Image 4 What are there functions? In the introduction page, the formation of electromagnetic waves were discussed. How a magnetron creates the electromagnetic wave is as follows: Inside of the magnetron’s vacuum tube, there is a cathode and
