What is a bimetallic strip simple definition?

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 why does it bend on heating?

Bimetallic strips are used as switches in thermostats. bi-metalic strips bend when heated Two metals making up the strip have different rates of expansion, so as heat is applied and the metals expand, one metal will expand faster than the other, causing that side to grow longer faster than the other side.

How does a bimetallic iron strip work?

Bimetallic stripes As the name implies, a bimetallic strip consists of two different types of metal – with different coefficients of expansion – that are bonded together. This means that in the presence of heat, they expand differently. This bimetallic strip is connected to a contact spring by small pins.

What happens when bimetallic strip is heated?

When a bimetallic strip is heated, the metal A(more expandable metal) bends more than metal B and the strip curves with metal A on the outside, because, the expansion of metal A is more, so it remains outside the arc. And if the strip is cooled, metal B will be on the outside.

Why does a bimetallic strip of brass and iron bend on heating?

When the bimetallic strip is heated, brass expands more than steel due to higher thermal coefficient than steel. 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.

How does a bimetallic strip work in a refrigerator?

In a refrigerator, the reverse set-up is used. When the temperature inside the refrigerator rises, the bimetallic strip bends to switch on the compressor which starts the cooling cycle. When a resistance indicating a particular temperature is reached, the heating elements is switched on or off.

What happens to bimetallic strip when heated?

When this bimetallic strip is heated, the brass expands more than the steel and the strip curves with the brass on the outside. If the strip is cooled, it curves with the steel on the outside. Bimetallic strips are used as switches in thermostats.

What is the function of thermostat in iron?

The main function of the thermostat in an electric iron is to make sure that the iron doesn’t get too hot if it is left unattended to for a period of time. When an electric current is passed through a coil in an electric iron, the coil becomes very hot.

How does a bimetallic strip work in a fire alarm?

When the strip is heated by fire, the high-expansion side bends the strip toward an electrical contact. When the strip touches that contact, it completes a circuit that triggers the alarm to sound. The width of the gap between the contacts determines the temperature that will set off the alarm.

Why bimetallic strip is used in iron?

The thermostat in iron generally uses a bimetallic strip. As the name implies, a bimetallic strip consists of two different types of metal – with different coefficients of expansion – that are bonded together. Therefore, the iron seems to switch on and off repeatedly during the ironing process.

Why do we use bimetallic strips in thermostats?

Bimetallic strips are used in thermostats for measuring and controlling temperature. The strip is connected to a switch and as the temperature changes the strip flexes and opens or closes a contact. They are also used in ovens for measuring temperature.

How does bimetallic strip work in an iron?

Which two metals are used in a bimetallic strip?

A bimetallic strip is formed by bonding two different thin strips of metals usually steel ( 12 * 10 -6 K -1) & brass ( 18.7 * 10 -6 K -1 ), or copper ( 16.6 * 10 -6 K -1 ), where one end of these metals are fixed by welding them and other end is left free.

Why are bimetallic strips used in thermostats?

Bimetallic strip thermometers are mechanical thermometers. They are widely used in industry for temperature control because of their robustness, temperature range and simplicity . It consists of a bimetallic strip which is made of two dissimilar’ metals bonded together with one end fixed and the other free.

What is the operating principle of a bimetallic strip?

Definition: A bimetallic strip works on the principle of thermal expansion , which is defined as the change in volume of metal with the change in temperature. The bimetallic strip works on two basic fundamentals of metals.

What does the bimetallic strip do in a thermostat?

Thermostats . In these, one end of the bimetallic strip is mechanically fixed and attached to an electrical power source, while the other (moving) end carries an electrical contact. In adjustable thermostats another contact is positioned with a regulating knob or lever. The position so set controls the regulated temperature, called the set point .