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59-481: A toaster is a small electric appliance that uses radiant heat to brown sliced bread into toast , the color caused from the Maillard reaction . It typically consists of one or more slots into which bread is inserted, and heating elements , often made of nichrome wire , to generate heat and toast the bread to the desired level of crispiness . In a pop-up or automatic toaster, a single vertical piece of bread

118-416: A magnesium oxide powder and the sheath is normally constructed of a copper or steel alloy. To keep moisture out of the hygroscopic insulator, the ends are equipped with beads of insulating material such as ceramic or silicone rubber, or a combination of both. The tube is drawn through a die to compress the powder and maximize heat transmission. These can be a straight rod (as in toaster ovens ) or bent to

177-414: A few U.S. dollars, or very expensive, such as an elaborate espresso maker , which may cost several thousand U.S. dollars. Most homes in developed economies contain several cheaper home appliances , with perhaps a few more expensive appliances, such as a high-end microwave oven or mixer . A small appliances like chopper, juicer , grinder and mixer may cost you few dollars. Instead of buying separate units

236-475: A home version and a commercial version, for example waffle irons , food processors , and blenders are small household appliances . A food processor will perform the tasks of chopper, slicer, mixer as well as juicer. Instead of buying multiple small appliances you can buy a single food processor. The commercial, or industrial, version is designed to be used nearly continuously in a restaurant or other similar setting. Commercial appliances are typically connected to

295-431: A limited amount of baking and broiling capability. Similarly to a conventional oven, toast or other items are placed on a small wire rack, but toaster ovens can heat foods faster than regular ovens due to their small volume. They are especially useful when the users do not also have a kitchen stove with an integral oven, such as in smaller apartments and recreational vehicles such as truck campers . A conveyor toaster

354-409: A long, tubular form or an R40 reflector-lamp form. The reflector lamp style is often tinted red to minimize the visible light produced; the tubular form comes in different formats: Removable ceramic core elements use a coiled resistance heating alloy wire threaded through one or more cylindrical ceramic segments to make a required length (related to output), with or without a center rod. Inserted into

413-406: A lower oxidation resistance than the active material. Heating elements are generally classified in one of three frameworks: suspended, embedded, or supported . Tubular or sheathed elements (also referred to by their brand name, Calrods® ) normally comprise a fine coil of resistance wire surrounded by an electrical insulator and a metallic tube-shaped sheath or casing. Insulation is typically

472-600: A metal sheath or tube sealed at one end, this type of element allows replacement or repair without breaking into the process involved, usually fluid heating under pressure. Etched foil elements are generally made from the same alloys as resistance wire elements, but are produced with a subtractive photo-etching process that starts with a continuous sheet of metal foil and ends with a complex resistance pattern. These elements are commonly found in precision heating applications like medical diagnostics and aerospace. Resistive heaters can be made of conducting PTC rubber materials where

531-496: A more powerful electrical outlet, are larger and stronger, have more user-serviceable parts, and cost significantly more. These commercial versions are capable of performing heavy tasks in one go. Small appliances include those used for : Many small appliances perform a combination of the above processes such as mixing, heating by a bread machine Small appliances can be very inexpensive, such as an electric can opener , hot pot , toaster , or coffee maker which may cost only

590-418: A power source. They generally are made of conductive materials such as copper that do not have as high of a resistance to oxidation as the active resistance material. Heating element terminals serve to isolate the active resistance material from the leads. Terminals are designed to have a lower resistance than the active material by having with a lower resistivity and/or a larger diameter. They may also have

649-482: A pre-coded phone number to get the weather forecast. In 2005, Technologic Systems, a vendor of embedded systems hardware, designed a toaster running the NetBSD Unix-like operating system as a sales demonstration system. In 2012, Basheer Tome, a student at Georgia Tech , designed a toaster using color sensors to toast bread to the exact shade of brown specified by a user. A toaster that used Twitter

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708-513: A range of appearances beyond just a square box and may have an exterior finish of chrome , copper , brushed metal , or any colored plastic . The marketing and price of toasters may not be an indication of quality for producing good toast. A typical modern two-slice pop-up toaster can draw from 600 to 1200 watts . Beyond the basic toasting function, some pop-up toasters offer additional features such as: Invented in 1910, toaster ovens are small electric ovens that provide toasting capability plus

767-491: A rate of 250–1800+ slices an hour. The total radiant heat a conveyor toaster applies to each slice can be controlled by adjusting the conveyor speed or the output strength of the heating elements. Conveyor toasters are generally available with either a vertical or horizontal conveyor orientation. Conveyor toasters have been produced for home use; in 1938, for example, the Toast-O-Lator went into limited production. Before

826-405: A rectangular cross-section with rounded corners. Generally ribbon widths are between 0.3 and 4 mm. If a ribbon is wider than that, it is cut out from a broader strip and may instead be called resistance strip . Compared to wire, ribbon can be bent with a tighter radius and can produce heat faster and at a lower cost due to its higher surface area to volume ratio. On the other hand, ribbon life

885-437: A regular toaster, except that there are two slots in the middle for hot dogs and two slots on the outside for toasting the buns. Or there can be a set of skewers upon which hot dog are impaled. Small appliance Some small appliances perform the same or similar function as their larger counterparts. For example, a toaster oven is a small appliance that performs a similar function as an oven . Small appliances often have

944-564: A shape to span an area to be heated (such as in electric stoves , ovens , and coffee makers ). Screen-printed metal–ceramic tracks deposited on ceramic -insulated metal (generally steel) plates have found widespread application as elements in kettles and other domestic appliances since the mid-1990s. Radiative heating elements (heat lamps) are high-powered incandescent lamps that run at less than maximum power to radiate mostly infrared instead of visible light. These are usually found in radiant space heaters and food warmers, taking either

1003-414: A toaster with an automatic bread turner. Before this, electric toasters cooked bread on one side, meaning the bread needed to be flipped by hand to cook both sides. Copeman's toaster turned the bread around without having to touch it. The automatic pop-up toaster, which ejects the toast after toasting it, was first patented by Charles Strite in 1921. In 1925, using a redesigned version of Strite's toaster,

1062-593: A type of resistive heater that can be printed on a thin substrate. Thick-film heaters exhibit various advantages over the conventional metal-sheathed resistance elements. In general, thick-film elements are characterized by their low-profile form factor, improved temperature uniformity, quick thermal response due to low thermal mass, high energy density, and wide range of voltage compatibility. Typically, thick-film heaters are printed on flat substrates, as well as on tubes in different heater patterns. These heaters can attain power densities of as high as 100 W/cm depending on

1121-458: A variety of mechanical, thermal, and electrical properties. Due to the wide range of operating temperatures that these elements withstand, temperature dependencies of material properties are a common consideration. Resistance heating alloys are metals that can be used for electrical heating purposes above 600 °C in air. They can be distinguished from resistance alloys which are used primarily for resistors operating below 600 °C. While

1180-409: Is a requirement of two or more heating zones with different power densities over a relatively small area, a thick-film heater can be designed to achieve a zonal heating pattern on a single substrate. Thick-film heaters can largely be characterized under two subcategories – negative-temperature-coefficient (NTC) and positive-temperature-coefficient (PTC) materials – based on

1239-601: Is always toasted to the same consistency. Several projects have added advanced technology to toasters. In 1990, Simon Hackett and John Romkey created "The Internet Toaster", a toaster that could be controlled by the Internet . In 2001, Robin Southgate from Brunel University in England created a toaster that could toast a graphic of the weather prediction (limited to sunny or cloudy) onto a piece of bread. The toaster dials

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1298-404: Is an appliance that caramelizes and carries bread products on a belt or chain into and through a heated chamber. Conveyor toasters are designed to make many slices of toast and are generally used in the catering industry, restaurants, cafeterias, institutional cooking facilities, and other commercial food service situations where constant or high-volume toasting is required. Bread can be toasted at

1357-486: Is defined by Pouillet's law as R = ρ ℓ A {\displaystyle R=\rho {\frac {\ell }{A}}} where The resistance per wire length (Ω/m) of a heating element material is defined in ASTM and DIN standards. In ASTM, wires greater than 0.127 mm in diameter are specified to be held within a tolerance of ±5% Ω/m and for thinner wires ±8% Ω/m. Heating element performance

1416-411: Is dropped into a slot on the top of the toaster. A lever on the side of the toaster is pressed down, lowering the bread into the toaster and activating the heating elements . The length of the toasting cycle (and therefore the degree of toasting) is adjustable via a lever, knob, or series of pushbuttons, and when an internal device determines that the toasting cycle is complete, the toaster turns off and

1475-473: Is mounted various attachments so as to constitute several individual appliances, such as a blender, a food processor, or a juicer . Many stand mixers , while functioning primarily as a mixer, have attachments that can perform additional functions. A few gasoline and gas -powered appliances exist for use in situations where electricity is not expected to be available, but these are typically larger and not as portable as most small appliances. Items that perform

1534-618: Is often quantified by characterizing the power density of the element. Power density is defined as the output power , P, from a heating element divided by the heated surface area , A, of the element. In mathematical terms it is given as: Φ = P / A {\displaystyle \Phi =P/A} Power density is a measure of heat flux (denoted Φ) and is most often expressed in watts per square millimeter or watts per square inch . Heating elements with low power density tend to be more expensive but have longer life than heating elements with high power density. In

1593-512: Is often shorter than wire life and the price per unit mass of ribbon is generally higher. In many applications, resistance ribbon is wound around a mica card or on one of its sides. Resistance coil is a resistance wire that has a coiled shape. Coils are wound very tightly and then relax to up to 10 times their original length in use. Coils are classified by their diameter and the pitch, or number of coils per unit length. Heating element insulators serve to electrically and thermally insulate

1652-464: Is used. A thinner wire or ribbon will always have a shorter life than a thicker one at the same temperature. Standardized life tests for resistance heating materials are described by ASTM International . Accelerated life tests for Ni-Cr(Fe) alloys and Fe-Cr-Al alloys intended for electrical heating are used to measure the cyclic oxidation resistance of materials. Resistance wire and ribbon are most often shipped wound around spools . Generally

1711-478: The Sunbeam Radiant Control toaster models made from the late 1940s through the 1990s, began the toasting cycle. These toasters use the mechanically multiplied thermal expansion of the resistance wire in the center element assembly to lower the bread; the inserted slice of bread trips a lever switch to activate the heating elements and their thermal expansion is harnessed to lower the bread. When

1770-473: The food processor will be less expensive. Sometime these kind of smart appliances saves money as well as the space. Many small appliances are powered by electricity . The appliance may use a permanently attached cord that is plugged into a wall outlet or a detachable cord. The appliance may have a cord storage feature. A few hand-held appliances use batteries , which may be disposable or rechargeable. Some appliances consist of an electrical motor upon which

1829-415: The resistivity increases exponentially with increasing temperature. Such a heater will produce high power when it is cold, and rapidly heat itself to a constant temperature. Due to the exponentially increasing resistivity, the heater can never heat itself to warmer than this temperature. Above this temperature, the rubber acts as an electrical insulator. The temperature can be chosen during the production of

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1888-515: The United States, power density is often referred to as 'watt density.' It is also sometimes referred to as 'wire surface load.' Resistance wire s are very long and slender resistors that have a circular cross-section. Like conductive wire , the diameter of resistance wire is often measured with a gauge system, such as American Wire Gauge (AWG) . Resistance ribbon heating elements are made by flattening round resistance wire, giving them

1947-563: The Waters Genter Company introduced the Model 1-A-1 Toastmaster, the first automatic, pop-up, household toaster that could brown bread on both sides simultaneously, set the heating element on a timer, and eject the toast when finished. In the 1980s, some high-end U.S. toasters featured automatic toast lowering and raising without the need to operate levers – simply dropping the bread into one of these "elevator toasters", such as

2006-559: The ambient. Heating elements may be used to transfer heat via conduction , convection , or radiation . They are different from devices that generate heat from electrical energy via the Peltier effect , and have no dependence on the direction of electrical current. Materials used in heating elements have a relatively high electrical resistivity , which is a measure of the material's ability to resist electric current. The electrical resistance that some amount of element material will have

2065-651: The chosen substrate materials. This is primarily attributed to the thermal characteristics of the substrates. There are several conventional applications of thick-film heaters. They can be used in griddles, waffle irons, stove-top electric heating, humidifiers, tea kettles, heat sealing devices, water heaters, clothes irons and steamers, hair straighteners, boilers, heated beds of 3D printers , thermal print heads, glue guns, laboratory heating equipment, clothes dryers, baseboard heaters, warming trays, heat exchangers, deicing and defogging devices for car windshields, side mirrors, refrigerator defrosting, etc. For most applications,

2124-500: The development of the electric toaster, sliced bread was toasted by placing it in a metal frame or on a long-handled toasting fork and holding it near a fire or over a kitchen grill. From the 16th century onward, long-handled forks were used as toasters, "sometimes with fitment for resting on bars of grate or fender." Wrought-iron scroll-ornamented toasters appeared in Scotland in the 17th century. Another wrought-iron toaster

2183-481: The effect of temperature changes on the element's resistance. NTC-type heaters are characterized by a decrease in resistance as the heater temperature increases and thus have a higher power at higher temperatures for a given input voltage. PTC heaters behave in an opposite manner with an increase of resistance and decreasing heater power at elevated temperatures. This characteristic of PTC heaters makes them self-regulating, as their power stabilizes at fixed temperatures. On

2242-531: The heat transfer conditions. The thick-film heater patterns are highly customizable based on the sheet resistance of the printed resistor paste. These heaters can be printed on a variety of substrates including metal, ceramic, glass, and polymer using metal- or alloy-loaded thick-film pastes. The most common substrates used to print thick-film heaters are aluminum 6061-T6, stainless steel, and muscovite or phlogopite mica sheets. The applications and operational characteristics of these heaters vary widely based on

2301-573: The heating element was solved in 1905 by a young engineer named Albert Marsh , who designed an alloy of nickel and chromium , which came to be known as nichrome . The first US patent application for an electric toaster was filed by George Schneider of the American Electrical Heater Company of Detroit in collaboration with Marsh. One of the first applications that the Hoskins company considered for its Chromel wire

2360-688: The instructions carefully and that appliances that use a grounded cord be attached to a grounded outlet . Because of the risk of fire, some appliances have a short detachable cord that is connected to the appliance magnetically . If the appliance is moved further than the cord length from the wall, the cord will detach from the appliance. Designations and regulations of "small appliances" vary by country and are not simply determined by physical sizes. For instance, United States Environmental Protection Agency regulations mandate that small appliances must meet two standards: The designations and regulations of "small appliances" are very important in order to assure

2419-463: The invention of the first successful incandescent lightbulbs by Joseph Swan and Thomas Edison . However, the light bulb took advantage of the presence of a vacuum, something that could not be used for the toaster. The first stand-alone electric toaster, the Eclipse, was made in 1893 by Crompton & Company of Chelmsford, Essex. Its bare wires toasted bread on one side at a time. The problem of

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2478-422: The majority of atoms in these alloys correspond to the ones listed in their name, they also consist of trace elements. Trace elements play an important role in resistance alloys, as they have a substantial influence on mechanical properties such as work-ability, form stability, and oxidation life. Some of these trace elements may be present in the basic raw materials, while others may be added deliberately to improve

2537-617: The other hand, NTC-type heaters generally require a thermostat or a thermocouple in order to control the heater runaway. These heaters are used in applications which require a quick ramp-up of heater temperature to a predetermined set-point as they are usually faster-acting than PTC-type heaters. An electrode boiler uses electricity flowing through streams of water to create steam. Operating voltages are typically between 240 and 600 volts, single or three-phase AC . Laser heaters are heating elements used for achieving very high temperatures. Materials used in heating elements are selected for

2596-433: The other hand, the aluminum oxide layer that forms on the surface of Fe-Cr-Al alloys is more thermodynamically stable than the chromium oxide layer that tends to form on Ni-Cr(Fe), making Fe-Cr-Al better at resisting corrosion. However, humidity may be more detrimental to the wire life of Fe-Cr-Al than Ni-Cr(Fe). Fe-Cr-Al alloys, like stainless steels, tend to undergo embrittlement at room temperature after being heated in

2655-621: The performance of the material. The terms contaminates and enhancements are used to classify trace elements. Contaminates typically have undesirable effects such as decreased life and limited temperature range. Enhancements are intentionally added by the manufacturer and may provide improvements such as increased oxide layer adhesion, greater ability to hold shape, or longer life at higher temperatures. The most common alloys used in heating elements include: Ni-Cr(Fe) resistance heating alloys, also known as nichrome or Chromel , are described by both ASTM and DIN standards. These standards specify

2714-427: The relative percentages of nickel and chromium that should be present in an alloy. In ASTM three alloys that are specified contain, amongst other trace elements: Nichrome 80/20 is one of the most commonly used resistance heating alloys because it has relatively high resistance and forms an adherent layer of chromium oxide when it is heated for the first time. Material beneath this layer will not oxidize, preventing

2773-399: The resistance heater from the environment and foreign objects. Generally for elements that operate higher than 600 °C, ceramic insulators are used. Aluminum oxide , silicon dioxide , and magnesium oxide are compounds commonly used in ceramic heating element insulators. For lower temperatures a wider range of materials are used. Electrical leads serve to connect a heating element to

2832-444: The rubber. Typical temperatures are between 0 and 80 °C (32 and 176 °F). It is a point-wise self-regulating and self-limiting heater . Self-regulating means that every point of the heater independently keeps a constant temperature without the need of regulating electronics. Self-limiting means that the heater can never exceed a certain temperature in any point and requires no overheat protection. Thick-film heaters are

2891-570: The safety of the public. Here are some rules and regulations for small appliances: Heating element A heating element is a device used for conversion of electric energy into heat, consisting of a heating resistor and accessories. Heat is generated by the passage of electric current through a resistor through a process known as Joule heating . Heating elements are used in household appliances, industrial equipment, and scientific instruments enabling them to perform tasks such as cooking, warming, or maintaining specific temperatures higher than

2950-418: The same function as small appliances but are hand-powered are generally referred to as tools or gadgets , for example a hand cranked egg beater , a grater , a mandoline , or a hand-powered meat grinder . Small appliances which are defective or improperly used or maintained may cause house fires and other property damage, or may harbor bacteria if not properly cleaned . It is important that users read

3009-413: The temperature range of 400 to 575 °C for an extended duration. Heating elements find application in a wide range of domestic, commercial, and industrial settings: The life of a heating element specifies how long it is expected to last in an application. Generally heating elements in a domestic appliance will be rated for between 500 and 5000 hours of use, depending on the type of product and how it

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3068-412: The thermal performance and temperature distribution are the two key design parameters. In order to maintain a uniform temperature distribution across a substrate, the circuit design can be optimized by changing the localized power density of the resistor circuit. An optimized heater design helps to control the heating power and modulate the local temperatures across the heater substrate. In cases where there

3127-504: The thinner the wire, the smaller the spool. In some cases pail packs or rings may be used instead of spools. General safety requirements for heating elements used in household appliances are defined by the International Electrotechnical Commission (IEC) . The standard specifies limits for parameters such as insulation strength, creepage distance, and leakage current. It also provides tolerances on

3186-406: The toast is done, as determined by a small bimetallic sensor actuated by the heat radiating off the toast, the heaters are shut off and the pull-down mechanism returns to its room-temperature position, slowly raising the finished toast. This sensing of the heat radiating off the toast means that regardless of the type of bread (white or whole grain) or its initial temperature (even frozen), the bread

3245-572: The toast pops up out of the slots. The completion of toasting may be determined by a timer (sometimes manually set) or by a thermal sensor, such as a bimetallic strip , located close to the toast. Toasters may also be used to toast other foods such as teacakes , toaster pastries , potato waffles and crumpets , though the resultant accumulation of fat and sugar inside the toaster can contribute to its eventual failure. Among pop-up toasters, those toasting two slices of bread are more purchased than those that can toast four. Pop-up toasters can have

3304-461: The wire from breaking or burning out. Fe-Cr-Al resistance heating alloys, also known as Kanthal® , are described by an ASTM standard. Manufacturers may opt to use this class of alloys as opposed to Ni-Cr(Fe) alloys to avoid the typically relatively higher cost of nickel as a raw material compared to aluminum. The tradeoff is that Fe-Cr-Al alloys are more brittle and less ductile than Ni-Cr(Fe) ones, making them more delicate and prone to failure. On

3363-431: Was cited as an early example of an application of the Internet of Things . Toasters have been used as advertising devices for online marketing . With permanent modifications, a toaster oven can be used as a reflow oven to solder electronic components to circuit boards . A hot dog toaster is a variation on the toaster design; it can cook hot dogs without the use of microwaves or stoves. The appliance looks similar to

3422-559: Was documented to be from 18th-century England. Utensils for toasting bread over open flames appeared in America in the early 19th century, including decorative implements made from wrought iron. The primary technical problem in toaster development at the turn of the 20th century was the development of a heating element that would be able to sustain repeated heating to red-hot temperatures without breaking or becoming too brittle. A similar technical challenge had recently been surmounted with

3481-543: Was for use in toasters, but the company eventually abandoned such efforts, to focus on making just the wire itself. The first commercially successful electric toaster was introduced by General Electric in 1909 for the GE model D-12. In 1913, Lloyd Groff Copeman and his wife Hazel Berger Copeman applied for various toaster patents, and in that same year, the Copeman Electric Stove Company introduced

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