GK Glass or Ceramic Casing (internal)

Hf Heater Element

P ₁ P ₂ Anodes

M Permanent Magnet

M: Circular Permanent Magnet

The capacitor C and inductor L are not external parts, but are built in to the component.

The first Magnetrons were developed by the English during the Second World War for use in RADAR equipment. These achieved several kilowatts of power with frequencies from 700 to 30,000 MHz. These were pulsed for ten seconds. Verifying this translation on the pulse duration. KO

The magnetic field is aligned parallel to the heater element and the two anodes. Electrons, which leave the heater element, move under the influence of the magnetic field (from the permanent magnet) on circular courses within the anodes instead of a straight line to the anode.. This effect produces a so called "negative internal resistance" (impedance?), with which, the Magnetron produces oscillations. The frequency of these oscillations is determined by the values of the capacitor   C and the inductor  L. Certain constructions do not need a resonant circuit. The circular path of the electrons determines the wavelength of the oscillation. In this way wavelengths can be achieved of less than one Centimeter (as in magnetrons for microwave ovens). Microwaves can easily heat aqueous materials. It is lethal to be close to the antenna of a large radar device. Microwaves of approximately 8OO Watts of continuous duty can cause so much heating in close proximity of the antenna that they are used for cooking and roasting in household microwave ovens. However these must have shielding to protect the user from radiation.