What Is A Bimetallic Strip

noun. a strip consisting of two metals of different coefficients of expansion welded together so that it buckles on heating: used in thermostats, etc.

What is a bimetallic strip and how does it work?

The bimetallic strip constitutes one of the most trouble-free and durable thermometers. It is simply two strips of different metals bonded together and held at one end. When heated, the two strips expand at different rates, resulting in a bending effect that is used to measure…

What is a bimetallic strip where is it used?

Bimetal strips are used in miniature circuit breakers to protect circuits from excess current. A coil of wire is used to heat a bimetal strip, which bends and operates a linkage that unlatches a spring-operated contact. This interrupts the circuit and can be reset when the bimetal strip has cooled down.

What is an example of bimetallic strip?

Thermometer and thermostat are examples of bimetallic tip devices. (i) Thermometers: A thermometer uses a bimetallic strip, generally wrapped into a coil in its most used design. The coil changes the linear movement of the metal expansion into a circular movement due to the helicoidal shape it draws.

What is bimetallic strip why does it bend on heating?

A bimetallic strip consists of a strip of two different metals welded together. When we heat it, different metals expand by different amounts. It bends due to thermal expansion.

How does a bimetallic strip break a circuit when things heat up?

The bimetallic strip is made up of two different metals which are bonded together to form a straight, flat strip or a concentric coil. When the strip is heated, one of the metals heats up and expands faster than the other, causing the strip to bend.

How does bimetallic strip work in an iron?

At normal room temperature, the two strips have the same length. However, since brass expands (or contracts) more than iron when its temperature is raised (or cooled), the bimetallic strip will bend one way or another depending on the temperature being above or below room temperature.

How does a bimetallic thermostat work?

Bimetal Thermostats use two different kinds of metal to regulate the temperature setting. When one of the metals expands more quickly than the other, it creates a round arc, like a rainbow. As the temperature changes, the metals continue to react differently, operating the thermostat.

Why do we use bimetallic lugs?

Bimetallic Lugs are mostly useful where an aluminum cable has to be terminated by a copper bus bar or copper contact. If Cable Lugs of only copper or aluminum are used , a galvanic action occurs due to dissimilar contact. The use of bimetallic lugs thus ensures a technically sound and durable joint.

What is bimetal and its properties?

Bimetals work with the propensity of metals to expand when heated, and contract when cooled. The resulting change of curvature, or bending, in response to temperature change, is a fundamental property of all thermostatic bimetals. In effect, the temperature change is converted into mechanical displacement.

Why does a bimetallic strip bend when cooled?

Brass and Iron together form the bimetallic strip. The rate of expansion and contraction of brass is more when compared to Iron, that is, brass expands more than Iron when heated and contracts faster than iron when cooled. As a result, the bimetallic strip bends with the change in temperature.

On which side does a bimetallic strip bend?

Bi-metallic strips are subject to bending due to heat - and can be used to convert change in temperature to mechanical displacement. Bending occurs towards the side of the metal with the lowest temperature coefficient of expansion.

Why does a bimetallic strip of brass and iron bend when heated?

higher thermal expansion coefficient means that substance will expand more as compared to any other substance per degree rise in temperature. And hence due to this phenomenon brass side shows higher expansion especially linear expansion than iron and hence forcing the whole bimetallic strip to bend.

What is bimetallic thermometer?

Bimetal thermometers are thermometers based on the functional principle that metals expand differently depending on the change in temperature. A bimetal thermometer always consists of two different metal strips that have a different thermal expansion coefficient.

Why do metal expand when heated?

What does heat do to metal? The expansion (or contraction) of any material is due to the kinetic energy of its atoms. When a material is heated, the increase in energy causes the atoms and molecules to move more and to take up more space— that is, to expand. This is true of even a solid such as a metal.

What material expands the most when heated?

Gases expand the most upon heating because the intermolecular space is more than in solids or liquids.

Why do substances expand when heated?

When we heat a substance its molecules gain energy and start vibrating rapidly and start expanding the length, area, and volume of the substance. As a result, a substance expands.

Does a refrigerator use a bimetallic strip?

Answer. When the temperature inside the refrigerator rises, the bimetallic strip bends to switch on the compressor which starts the cooling cycle.

In what situation should you use a bimetallic thermometer?

The bimetallic thermometer is used in household devices likes oven, air conditioner, and in industrial apparatus like refineries, hot wires, heater, tempering tanks etc. for measuring the temperature.

What are the advantages and disadvantages of bimetallic thermometer?

advantages	disadvantages
Bimetallic thermometer *
cheap	requires frequent calibration to maintain accuracy
durable	fairly slow response
can be used for thermograph