In this brief guide, we will answer the question, ‘how does a toaster work?’. We will explore the technical aspects of how the toaster works and the reason and factors that contribute to the toasting process.
How does a toaster work?
The toaster works by taking in electricity and producing heat in the form of infrared radiation. The coils inside the toaster turn red while producing infrared radiation. As the radiation transfers its heat, you see the familiar charred bread.
To work a toaster; plug it in, pop the bread slice into the slot. The bread will pop out according to the power and time setting.
A spring-loaded tray causes the bread to jump out of the slot on its own. A timer works in coordination; as the bread gets ready, the toaster turns itself off and releases the tray and the slice of bread on it.
How does a toaster create infrared radiation?
Infrared radiations are produced with help from nichrome wire. The nichrome wires are an alloy, a mixture of nickel and chromium. They are wrapped on 2 mica sheets which form the lining of the slot.
The heat from the infrared radiations causes browning on not only the surface but penetrates through as well. The heat makes the molecules move faster, which speeds up the browning process.
The wires glow red as they absorb energy and emit light; which is released when the wire becomes unstable.
Infrared Radiations makes the bread caramelize by the process known as the milliard reaction. Bread constituents the sugars and starch, both undergo a chemical reaction to produce the familiar color, texture, and taste of the bread.
The chemical reaction occurs between sugars and proteins on the application of heat. The Millard reaction is not only in bread but some other foods as well.
Nichrome wire produces heat that is adequate and has a long life. They have a high electrical resistance which means that they do not need high power to get hot quickly. Nichrome wires do not rust because they can not oxidize like metals.
The nichrome sheets have a metal holder that has the job of raising the slots up and down.
The slots have grates that press against the bread to ensure that the bread stays inside the slot.
The holders present inside the slot, work in synchronization with the handle. When you push it down to lower the bread, the metal springs get pushed. While the bread continues to toast, the handle stays down, which keeps the toast inside.
Let us see how the power switch works in harmony with the hold-down switch:
A plastic plate is attached to the toast lowering lever, while to the handle, there is a piece of metal attached.
A pair of contact bars on the circuit board summoned by the plastic bar releases power to the nichrome wires. The induction of power makes it attracted to the electromagnet, which in turn holds the toast down.
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Let us closely look at how the plastic bar contributes to the mechanism of the toaster:
When you push the handle down, the plastic bar induces current to the circuit board, relayed by the contacts.
The 120 Volt power transmits through the nichrome wire, which starts the toasting process.
What causes the electromagnets to turn on and off?
There are either of two principles employed to control the electromagnets. The first one uses a variable resister, while the other one has a bimetallic strip.
Let us discuss the principle which makes use of variable resistors to toast the bread slices.
The circuit mainly relies on the transistor, resistors, and capacitors to turn on the electromagnet. The primary purpose of the circuit is to act as a timer.
As the resistor makes the capacitor charge, attaining the maximum voltage turns the electromagnet off. This signals the springs to pop out the bread slices while the plastic bar moves up as well.
To control the darkness of your bread, a variable resister comes to play. As the resistance varies, the capacitor charging varies with it.
The resistor and capacitor work together to determine how long until the toaster goes off.
Older models of toaster make use of bimetallic strips to turn the electromagnets off. The strips heat up as a result of the increasing temperature inside the machine and bend. The bending of the strip causes a trip which cuts off the power to the electromagnet.
The obsolete, less sophisticated use of bimetallic strips has a couple of drawbacks.
The temperature gradient of the ambient environment impacts when the electromagnet shuts off rather than the color of bread.
In this brief guide, we answered the question, ‘how does a toaster work?’. We explored the technical aspects of how the toaster works and the reason and factors that contribute to the toasting process.