Bimetallic strip

Bimetallic strip is a mechanical element that consists of two different metals or alloys, which are bonded together. This strip is used in a variety of applications, primarily for its unique property of bending or curving in response to changes in temperature.

Composition

A bimetallic strip is composed of two different metals, typically copper and iron, steel, or brass. These metals are chosen for their differing coefficients of thermal expansion, which is the rate at which they expand or contract in response to changes in temperature. The metal with the higher coefficient of thermal expansion is usually placed on the outer side of the strip.

Function

The primary function of a bimetallic strip is to convert a temperature change into mechanical displacement. When the strip is heated, the metal with the higher coefficient of thermal expansion expands more than the other metal. This causes the strip to bend or curve. Conversely, when the strip is cooled, it bends in the opposite direction. This property is utilized in a variety of applications, including thermostats, fire alarms, and oven controls.

Applications

Bimetallic strips are used in a wide range of applications due to their unique property of bending in response to temperature changes. Some of the most common applications include:

• Thermostats: In a thermostat, a bimetallic strip is used to break or make an electrical circuit based on the ambient temperature. When the temperature rises above a certain point, the strip bends and breaks the circuit, turning off the heating device. When the temperature falls below a certain point, the strip bends in the opposite direction and makes the circuit, turning on the heating device.

• Fire Alarms: In a fire alarm, a bimetallic strip is used to trigger the alarm when the temperature rises above a certain point. The strip bends and breaks a circuit, which triggers the alarm.

• Oven Controls: In an oven control, a bimetallic strip is used to regulate the temperature of the oven. The strip bends and breaks or makes a circuit based on the temperature inside the oven, turning the heating element on or off as needed.

See Also

• Thermal expansion
• Thermostat
• Fire alarm
• Oven control