कलयुग में कल्कि अवतार

TEMPERATURE TRANSDUCER

May 2019 by.  Jaroore suchanaa

Definition of Temperature Transducer

A Temperature Transducer is a device that converts the thermal quantity into any physical quantity such as mechanical energy, pressure and electrical signals etc.
E.g. In

href="https://www.electrical4u.com/thermocouple-temperature-measurement/" style="border: 0px; color: #be9e5f; margin: 0px; padding: 0px; text-decoration: none; transition: all 0s ease-in-out;">Thermocouple the electrical potential difference is produced due to temperature difference across its terminals. So, thermocouple is an temperature transducer.

Main Features of Temperature Transducers

• The input to them are always the thermal quantities
• They generally converts the thermal quantity into electrical quantity
• They are usually used for the measurement of the temperature and heat flow

Basic Scheme of Temperature Transducers

The basic scheme of temperature transducers is given below in following steps
Sensing Element
The sensing element in the temperature transducers is the element whose properties change with change in temperature. As the temperature changes the corresponding change occurs in certain property of the element.
Example- In the Resistance Thermometers the sensing element is the Platinum metal.
Desirable Conditions for Choosing the Sensing Element are as

• Change per unit resistance of material per unit change in temperature should be large
• The material should have a high resistivity so that minimum volume of material is used for its construction
• The material should have continuous and stable relationship with temperature
• Transduction Element
  It is the element that transforms the output of the sensing element into electrical quantity. The change in the property of the of sensing element acts as the output for it. It measures the change in the property of sensing element. The output is of transduction element is then calibrated to give output which represents the change in the thermal quantity.

Example- In the thermocouple the potential difference produced across the two terminal is being measured by voltmeter and magnitude of voltage produced after calibration gives idea of change in temperature.

Types of Temperature Transducers

Contact Temperature Sensor Types

In these the sensing element is in direct contact with the thermal source. They use the conduction for transfer of thermal energy.

Non-contact Temperature Sensor Types

In these the sensing element is not in direct contact with the thermal source. They use principle of convection for heat flow. Various temperature transducers that are generally Used,