Microwave Oven Essay Sample

kernels near the magnetron. He observed as the Zea mays everta made crackling and popping sounds throughout his laboratory, sparking a brilliant idea. The next day, Dr.

Spencer opted to place the magnetron tubing in close proximity to an egg and observed as the egg started trembling and shaking due to the quick escalation in temperature within. This created a significant level of internal pressure within the egg.

A couple of minutes later, the table was covered in hot egg yolk as it exploded. Spencer had a scientific insight; liquid candy bars, popcorn, and now exploding eggs.

The effects of low-density microwave energy were responsible for cooking an egg quickly. This led to speculation about whether other nutrients could also be cooked at a faster rate. It seemed plausible that microwave heating could achieve higher internal temperatures for various nutrients compared to a traditional oven. Dr. concluded that this was a logical conclusion.

Spencer created a metal box that had an opening where he introduced microwave power. The power was trapped inside the box, creating a denser electromagnetic field. Food placed in the box was exposed to the microwave energy.

Dr. Spencer's invention of the microwave oven led to a rapid rise in the temperature of nutrients and revolutionized cookery, laying the foundation for a multimillion dollar industry.

Here is the Original Microwave Oven Patent by Dr. Spencer, shown in Figure 1. After this, applied scientists put in effort to develop and refine Spencer's innovative idea for practical use.

In 1947, the first commercial microwave oven was introduced to the market, after the Raytheon Company had filed a patent in late 1945 proposing the use of microwaves for cooking

food nutrients.

Raytheon showcased the Radarange, the leading micro-cook oven in the world, which was both enormous and costly. Each unit stood at 5 1/2 feet in height, weighed over 750 pounds, and cost approximately $5000.

The installation of plumbing was necessary for the water cooling of the magnetron tubing. Initially, consumers were very hesitant about these early units, which is not surprising.

At first, the units were unattractive, bulky and unappealing, which resulted in low sales. However, this did not last for an extended period of time.

Between 1952 and 1955, advancements resulted in the creation of an improved and lighter oven that was not only cheaper but also no longer required a pipe fitter due to the development of a new air-cooled magnetron.

A theoretical model called the first-place was introduced by Tappan at a cost of $1295. Later in 1967, Raytheon introduced a 100-volt countertop microwave oven for domestic purposes, priced below $500. The new models were safer, more reliable, and smaller than the older ones.

The microwave oven has gained more credibility, specifically in certain industrial contexts. With its availability, businesses such as restaurants and food vendors can keep their products refrigerated until service, then heat them up as needed.

The microwave oven's potential and versatility were recognized by the food industry, leading to freshman food, reduced waste, and cost savings. This innovation has gained popularity and widespread use.

As the use of microwaves expanded, various industries found innovative ways to utilize this technology. They started using microwaves to dry Murphys French fries, roast coffee beans and peanuts. It also became possible to defrost, precook and temper meat using microwaves. In addition to these benefits, microwaves also

made shucking oysters easier.

Microwave heating has been discovered to have a range of benefits across different industries. One example is its use in drying materials like cork, ceramics, and paper.

The selection of goods comprises leather items, tobacco products, various fabrics, and pencils.

The commercial market's microwave oven could cook a variety of items, including flowers, moist books, and Lucifer heads. Over time, advancements in technology led to the creation of a consumer-friendly and affordable microwave oven that is now commonly used in kitchens.

Despite the many myths and fears associated with "radar scopes," people began to recognize the advantages of microwave cooking in the 1970s, as no cases of radiation poisoning were reported.

The decline of fear led to an emergence of trust in kitchens across America and other places, which fueled a trend towards uninformed travel and sterility. This ultimately caused a significant increase in microwave oven purchases, resulting in sales exceeding $1 billion by 1975.

Gas scopes were initially outdone by the first clip; however, micro-cook ovens quickly gained popularity and were installed in millions of US kitchens.

In 1976, the microwave oven became a more popular kitchen appliance than the dishwasher. It revolutionized cooking habits in America with its energy efficiency and time-saving convenience. Though once considered a luxury item, it had become an indispensable tool in a fast-paced world.

The magnetron, which is a type of electron tube functioning as a diode, generates 2450 MHz of microwave energy. This component lies at the core of every microwave oven and is responsible for cooking or heating food. It's worth noting that a wavelength of approximately 12 centimeters corresponds to a frequency of around 2.5 GHz.

The frequency utilized

is also commonly found in cordless phones, as well as in routers for radio connections. These devices are frequently used in households, educational institutions, and businesses.

Although there are different theoretical perspectives regarding the external components of microwave ovens, the internal parts remain consistent. These include the anode, filament/cathode, aerial, and magnets.

Figure 2: Typical Magnetron Structure
Anode: The anode is comprised of an Fe cylinder with inwardly extending anode vanes, forming an even figure. The unfastened trapezoidal shaped areas between each of the vanes function as resonating pits, serving as tuned circuits to determine the output frequency of the tube. To ensure proper operation, the anode requires that alternate sections be connected or strapped in a way that results in each section being opposite in mutual opposition to the section on either side.

The center of the magnetron holds the filament and cathode. These components are supported by strong fibril leads, which are sealed into the tubing and shielded. The aerial is a loop that connects to the anode and extends into one of the tuned pits for transmitting RF energy.

The utilization of strong lasting magnets placed around the magnetron enables a parallel magnetic field along the cathode axis. This crossed-field device known as a magnetron utilizes both electric and magnetic fields produced in perpendicular directions. The constant magnetic field applied remains unchanged during magnetron operation.

The device is powered by applying energy to the central cathode, causing it to emit energetic negatrons. These negatrons then travel outwards towards the surrounding ring anode in the absence of a magnetic field. The resonating pit produces hovering magnetic and electric fields.

By acting as inductance, the fluxing

currents around the pit generate a resonance that is reminiscent of a parallel LC resonant circuit. At the same time, the terminals of the pit act as capacitance and produce a natural resonant frequency. This frequency enables the pit to continue to pump through a process known as thermionic emission.

When a hot filament/cathode releases electrons, they are accelerated by the field towards the anode. However, the magnetic field exerts a force on the electrons causing them to be swept. As they sweep, they may encounter a point with excess negative charge which will cause them to loop back around the pit and transfer energy to oscillation at the natural resonating frequency of the pit. The result is the emission of electromagnetic waves.

Also called microwave radiation, the Microwave Oven operates as a high-potential system that takes in a regular AC voltage of approximately 115V and outputs a very-high DC voltage exceeding 2000V. This transformation is achieved through collaboration between the rectifying tube (rectifier) and capacitance to effectively double the already-high voltage.

The circuit present in a Microwave Oven that doubles the voltage is known as voltage-doubler circuit, as depicted in Figure 3. This circuit works as a sine wave, and during the positive half-wave, the rectifying tube charges the capacitor while the current flows through it. At first, there is no voltage since the capacitor is not charged yet.

During T1, the capacitance electric potential difference will increase to the upper limit of 2800 V due to the fluctuating current. Subsequently, when the transformer secondary electromotive force diminishes from its maximum positive value at T2, the capacitance discharges via the rectifying tube while maintaining its electric potential difference

at 2800 V. Finally, during T3, the transformer secondary electromotive force swings negatively in the negative half-cycle, reaching a negative value of 2800 V.

The transformer and charged capacitance create two energy sources in series, resulting in a combined electromotive force of 5600 V for the magnetron. The output is DC because a electromotive force doubler acts as a rectifier. This DC power is then transformed into RF energy within the magnetron to produce microwaves.

So, how does owning all this knowledge relate to how food is cooked? That's a great question! As shown in Figure 4, a microwave oven operates by using a magnetron to produce microwaves. These waves are then directed into the oven cavity through a waveguide, which is a tube comprised of a hollow metal conductor that could possibly include a dielectric material.

The metal interior wall of the oven is coated with epoxy pigment to efficiently direct and reflect microwaves.

The waves will come into contact with the food, even if they didn't initially. A unique screen on the microwave door prevents microwaves from escaping. The wave guide tube releases microwaves inside the microwave oven.

There are countries that experience fewer waves than others. If food were heated up in the same way, it would result in uneven temperatures. To address this issue, turning the food around in microwave ovens can effectively solve the problem.

Micro-cook ovens emit electromagnetic waves at a frequency of 2.5GHz, which is significant because this frequency is most easily absorbed by water, fats, and sugars - the primary components of common food. As a result, when these chemical compounds come in contact with these waves, they are impacted.

When molecules absorb straight

atomic gestures, they begin to move and revolve, resulting in a motion known as clash. This phenomenon occurs in all molecules as they interact and collide with each other.

It should be noted that the process of warming using H2O is distinct from conventional gas or electric oven heating. The former involves exciting atoms and making them hot wherever there is water, while the latter involves transferring heat from the outside to the interior. Furthermore, this difference is interesting.

That frequency range allows for non-absorption of moving waves in materials such as glass, paper, ceramics, and certain plastics.

The heat produced in these substances originates solely from the heat of the food. It is evident that electromagnetic theory is applicable universally, being present in our everyday lives through devices such as telephones and microwave ovens. The latter rely on three primary characteristics of electromagnetic waves: reflection.

Reflection and absorption of microwaves are commonly observed in our daily lives, including in the Elec351 class. For example, the metal walls inside a microwave oven reflect microwaves.

Microwaves are able to pass through materials like glass and certain types of plastic without causing harm. However, if an item is damp, it will absorb microwaves instead.

The collision of vibrating molecules in a moist object results in heat, which then heats up the food. Despite the initial negative reactions towards microwave ovens, the expanding market now offers a variety of sizes, shapes, and colors to accommodate different tastes and suit any kitchen.

There are options and features that can bring joy to every wallet, including the addition of convection heat and the use of investigation and detection cooking technology.

Microwave cooking has become a universally

demanded technique for both heating and drying in the realm of culinary arts. This once thought of as magic way of cooking has spread worldwide and become a global phenomenon.

The text mentions the topic of microwave ovens and provides two sources: the website on the topic found at "http://en.wikipedia.org/wiki/Microwave_oven," as well as the author J. Carlton Gallawa. These details are marked up with within a paragraph element.

J. published "The Complete Microwave Oven Service Handbook: Operation, Maintenance, Troubleshooting, and Repair" in 2004.3.

Carlton Gallawa's 1989-2001 piece titled "The Magnetron Tube Structure and Operation" can be found at hypertext transfer protocol://www.

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Nave's article titled "The Magnetron" from Georgia State University in 2000 can be accessed through the hypertext transfer protocol at http://hyperphysics.

The author J. Carlton Gallawa has written about the magnetron on the website phy-astr.gsu.edu/hbase/waves/magnetron.html.

"The Structure and Operation of the Magnetron Tube" from 1989-2001 can be found at hypertext transfer protocol: //www. gallawa.

The text enclosed in is a hyperlink to an article titled "The Microwave Oven Voltage-Doubler Circuit" authored by J. Carlton Gallawa. The article was published between 1997 and 1999 and can be found at the URL: http://www.com/microtech/doubler.hypertext markup language6.The URL "gallawa.com/microtech/magnetron.html" is enclosed within HTML paragraph tags.