This file contains full description of all parts of microwave and all kind of information related to microwave oven that could help you in technical terms.

1. MICROWAVE OVEN
A microwave oven creates radio waves at a frequency of about 2.45 GHz . All
radio waves are electromagnetic radiation.
When a polar molecule is placed in an electric field, it lines up with that field. It is
similar to how a compass needle lines up with a magnetic field. Depending on the
strength of the electric field, it will even stretch the polar molecule. But it will
spring back as soon as the electric field is removed. So, the way a microwave
works is, the rapidly oscillating electric field causes the polar molecules to move
back and forth, increasing their kinetic energy (or heat). When matter is heated,
the atoms and molecules start to vibrate faster. So far, it sounds like the heat
from microwaves is no different than the stove. But there is one major difference.
Microwaves have a strong electric field.
Electromagnetic radiation is a self-propagating wave composed of two
components: an electric field, and a magnetic field. The two fields expand and
collapse as they propagate through space. As the electric field collapses, it
produces an expanding magnetic field. Conversely, as the magnetic field
collapses, it produces an expanding electric field [4]. This is a simple explanation,
and there are more details involved.
If the electric field is strong enough, not only will it stretch the molecule, it can
also separate the charges enough so that an atom loses an electron. This is
ionizing. Or it can separate a molecule. This is similar to electrolysis.
When electricity flows in a conductor, free electrons drift easily in the direction of
the electric field. In a non-conductive material, the electrons are tightly bound to
the atoms. If the electric field is strong enough, electricity will flow. The non-
conductive material often gets destroyed when the electric field is strong enough
to ionize the atoms and force conduction, which creates a plasma such as a spark.
A plasma is made of ionized atoms or molecules. A plasma can be formed in a gas,
a solid, or even a liquid, but not in a pure vacuum. A plasma being formed in a
solid is a foreign concept to some, but familiar to semiconductor physicists. Once
the plasma is formed, the resistance drops very low and it conducts electricity
easily. This is why arc-welders don't need to use megawatt power supplies. The

2. plasma in the arc has a low resistance.
The electrical resistance of foods can range from low to very high. Many foods will
conduct some electricity when placed in an electric field. The electric field in the
microwave oven causes electric currents to flow in the food. This is similar to
what happens when an antenna picks up current from a radio wave.
Electrical current can also rearrange atoms. For example, in microchips, the wires
have to be big enough or the force of the electrons actually can move enough
metal so the wire distorts until it breaks [5].
If electric current can rearrange metal, it can also rearrange the atoms in your
food, changing the molecular structure. This happens either by ionization, or by
momentum transfer from the electron to the atom. This is one reason why
nutrients can be destroyed more easily in a microwave oven than on the stove.
Even though microwaves are classified as non-ionizing radiation, at sufficient
power levels, they can cause ionization such as a plasma [6, 7, 8].
Despite the slang term 'nuke', microwaves are not nuclear radiation. Nuclear
radiation consists of high speed alpha particles (helium nucleus), beta particles
(high velocity electrons), neutrinos, gamma rays (extremely high energy photons),
or high speed neutrons [9]. Nuclear radiation is classified as ionizing radiation [10]
because it will ionize matter at any level of radiation. Every radioactive particle
has the potential to ionize when it interacts with matter.
Ionizing, or simply displacing a single electron sounds harmless enough, but this is
enough energy to destroy biological molecules. This is what kills every living
organism that goes through the irradiation [11] process, including the food. Cold
pasteurization (a nice name for irradiation) really is nuking your food.
There is a tendency for most microwave users to cook everything on high power,
except when defrosting. High is the default setting? The maximum power is also a
major selling point for a microwave oven. The higher the power, the stronger the
electric field and the more damaging it are to nutrients. So, lower the power, the
safer. But only some microwave ovens are capable of true low power cooking.
The microwave ovens equipped with inverter magnetrons actually reduce the

3. power instead of just cycling it between high and off.
I decided to try microwaving some audio CDs to prove that the power level had an
effect on the amount of damage done while cooking to the same temperature.
Although it would be an honourable sacrifice in the name of science, rather than
use my wife's Barry Mani low collection, I thought it would be more prudent to
burn some songs onto identical CDs and experiment on those instead.
I set my inverter-magnetron microwave to cook at 30% power for 3 1/2 minutes. I
placed the CD in a plastic bowl and added 1 cup of water at 74°F. After cooking,
the temperature was 158°F. I dried off the CD and stuck it in my CD player. It still
played. All 16 songs were still ok. I then placed a second, identical CD in the bowl
and again added 1 cup of water. I cooked it for one minute on high power. It went
from 73°F to 162°F, so it got approximately the same amount of heat. But the CD
was visibly much damaged. The CD player obviously couldn't even read it.
Although this was a crude experiment, it illustrates the fact that cooking on high
power causes more damage than cooking on low power. So, the higher the
power, the more damage it causes, even if the final temperature is the same.
It is a well-known fact that raw food is more nutritious than cooked. Cooking food
destroys nutrients, whether it's on a stove, or in the microwave oven. But
microwaving food on high power can be more destructive than cooking on the
stove. So if you use a microwave, use one with an inverter magnetron, and cook
on low power. Cooking on true low power (not intermittent high) will greatly
reduce the amount of damage done to the food.
MAGNETRON
Description
A magnetron is an electric device that produces microwave energy by converting
electrical energy to radio frequency energy. It is commonly used as the heating element
in modern microwave ovens.
Construction
A magnetron is a type of diode, a special type of vacuum tube that converts low voltage
electrical energy to high voltage, then to radio frequency energy. A magnetron contains a

4. central cylindrical cathode within a thick cylinder that forms an anode shell. Along the
inside of the shell are resonance chambers with openings. Top and bottom plates seal the
cylinder, which is then placed within a powerful magnet.
Energy Conversion Process
When the cathode is heated, it gives off large amounts of negatively-charged electrons,
which the positively-charged anode will attract. This process converts and steps up the
low-voltage AC current, used to heat the cathode, to high-voltage DC current that flows
within the magnetron chamber.
Microwave Generation and Broadcast
The flow of this current is controlled by the strong magnetic field. As the electrons flow
within the vacuum, the resonance chambers within the walls of the anode emit very high
frequency energy in the form of a microwave field. This energy is then collected by an
antenna and sent through a wave guide, a type of tube that directs it with little or no loss.
The energy is then directed to another antenna that transmits the microwaves.
The Life Force of the Microwave Oven
The magnetron is the life force of the microwave oven. A microwave oven works by
sending microwaves of energy to the food, which causes the water content in the food to
heat rapidly, thereby rapidly heating the food. In order for this to happen, a high-voltage
system is necessary. The life force of this high-voltage system is the magnetron, which
uses a combination of electric and magnetic fields in order to create the microwaves that
"bounce" around the microwave to heat the food.
Internal Structure of the Magnetron
A magnetron is made up of the following parts:
* Anode/Plate: A hollow, iron cylinder that works with the cathode to
control the movement of the microwaved energy
* Cathode/Filament: In combination with electrical current, the
filament emits electrons that travel between itself and the anode
* Antenna: A probe that goes from the anode to the waveguide and
helps to guide the energy emitted from the magnetron
* Magnetic Field: Created by strong magnets that are mounted
around the magnetron to create a magnetic field parallel to the
cathode
How the Magnetron Works
The process begins when an electrical current is sent to the cathode/filament. The heat
that results from the electrical current causes an increase in molecular activity, thereby
emitting electrons into the space between the cathode and anode. Both the cathode and
the electrons are negative charges; the anode is a positive charge. This results in the
electrons moving away from the cathode and toward the anode, at higher rates of speed
as the temperature rises and causes more molecular activity.
The electrons follow the antenna toward the anode. During this process, the electrons
encounter the magnetic field, which detracts the electrons from their destination. The

5. forces of the electric charge, together with the magnetic field, cause the electrons to
travel in an ever-expanding circular orbit until the electron finally reaches the anode.
This circular motion of electrons is what produces the microwaves of energy that allows
food to be rapidly heated within the contained space of the microwave oven.