A sensor is a tool that measures a material quantity and transforms it into a signal which can be converted by the observer or by a device. For instance, the mercury in the thermometer glass transforms the measured temperature into extension and reduction of the liquid which can be translated on the glass tube calibrated. A thermocouple transforms the temperature to the voltage of output which can be interpreted by a voltmeter. For precision, all sensors have to be calibrated refer to the known standards.
Sensor is able to lift up and translate into electrical signal, used for input. Like thermocouple transforms the heat into a small voltage difference.
A transducer is a tool, generally electronic, electromagnetic, electro-mechanical, electrical, photovoltaic, or photonic that changes one kind of energy or attribute of physical to another for various purposes.
A transducer translates energy from one form to other form. Example: a motor that translates energy of electrical mechanical. A sensor senses and/or calculates the parameter.
1. A microphone detects sound and translates it to energy of electric.
2. A micro switch can sense or detect call between 2 objects and transform its state on or off.
A transducer and a sensor are frequently the similar thing as a microphone.
LVDT (Linear Variable Differential Transformer) is a secondary transducer that calculates force in voltage terms. Therefore, the output acquired is in the voltage form. Sensor is the tool that translates one form into the other form that can be assessed by a appropriate device or can be examined by an observer. For example: a thermometer. It assesses the temperature and for this reason demonstrates the reading of concordant. Transducer is using on input and output, but the majority for output. Transforming back signal of electric into sound wave of super high frequency, or utilize it as the sensor.