Transducers
Description
Transducers are electronic, electromagnetic, photovoltaic, electrical, electro-mechanical or photonic devices, which convert one form of energy to another form. Transducers convert electrical signals to physical parameters and vice versa. The physical parameters, such as linear displacement, current, pressure, ultrasonic wave, temperature, torque, velocity, voltage and air flow are measured, detected or produced by transducers. Generally, the term transducer is used in two senses; a sensor that is used for identifying a parameter, and like an audio loudspeaker that converts electrical voltage variation to mechanical vibration and thereby sound.
Types
Transducers are classified as:
Electromagnetic transducers (antenna, audio tape head )
Photoelectric transducers (laser diode, LED, photo resistor, phototransistor)
Thermoelectric transducers (resistance temperature detector, thermocouple)
Electrochemical transducers (pH probes, electro-galvanic fuel cell)
Electromechanical transducers (motor, load cell, potentiometer, relays, LVDT)
Electro acoustic transducers (loudspeaker, piezoelectric, earphone, microphone)
Electrostatic transducers (electrometer)
Radio acoustic transducers (radio receiver)
Specification
The specifications to be considered for transducers are given below:
Range
Frequency
Beam angle
Weight
Advantages
Transducers have many advantages, including compactness in size, high resolution, accuracy, noise-less operation, linearity and a wide range of availability. Transducers have proper standards, such as IEEE, AS1384, BS6253 and IEC688, which means that transducers can be found unique as per industrial standards. Several recording or indicating instruments can be attached to a single transducer without the need for any adjustments. Transducers can be short-circuited or open-circuited without any problems.
Applications
Transducers have many applications:
In medical equipment for monitoring heart beat, blood pressure; ultrasonic transducers for scanning, etc.
In electronic equipment and circuits for sensing physical parameters and for responding to a change in the physical parameter
Transducers such as loudspeakers, earphones, microphones, fans, fluorescent lights and radio receivers are used as home appliances
Transducers such as motors, relays, hydraulic transducers, pneumatic transducers and displacement sensors are used in industrial applications