What is electrical transducer
An electrical transducer is a transducer which can convert a non-electrical physical quantity into an electrical signal such as voltage, current or change in inductance resistance, capacitance. The output can be measured easily and it will be calibrated against an input. A transducer is composed of two parts the sensing element and transduction element. Sensing element is the sensor and it produces measurable response to change in the physical condition and the transduction element will convert the output of the sensor to a suitable output.
Electrical transducers are divided into
Input electrical transducer and out-put electrical transducer
An input electrical transducer will convert the mechanical input into electrical output whereas the out-put electrical transducer converts an electrical input to mechanical output
Types of electrical transducer
- Bridge circuits
- Wheatstone bridge
- Capacitive transducer
- Resistance transducer
- Magnetic sensor
- Piezoelectric transducer
- Strain gauges
- Photoelectric transducer
- Linear variable differential transformer
- Ultrasonic transducer
Electrical transducers based on nature of input
Potentiometers are used to measure electric potential and they are used to control the electric device such as volume controls on audio equipment. Potentiometer converts the change in displacement into a change in resistance.
Bridge circuits can convert the physical quantity to be measured into the voltage
Wheatstone bridge can be used to locate the breaks in the power lines. A Wheatstone bridge converts the displacement produced by the physical quantity to the current in the circuit
Capacitive sensors or variable capacitance transducers
Capacitive transducers are capacitors with the variable capacitance they are passive transducers and it is used for the measurement of displacement, pressure… it comprises two parallel plates between which there is a dielectric material like air the change in distance between the two plates produced by the displacement results in a change in capacitance which can be easily measured.
Resistive transducers are transducers in which the resistance will change due to the change in some physical phenomenon. When certain physical quantity is applied then there is a change in resistance in these sensors. Resistance transducers are most commonly used in resistance thermometers, thermistors for the temperature measurement
A magnetic sensor is a device which is capable of sensing a magnetic field and extracting information from it and the information is related to magnetic induction along an axis and is transduced by the sensor to an electrical signal. The input given to these sensors are in the form of displacement and the output obtained is in the form of change in inductance or reluctance and production of the eddy currents
Major function of this transducer is to convert mechanical energy to electrical energy and then electrical into mechanical energy. When force is applied to these transducers they produce a voltage that can be measured easily they are used for the measurement of pressure, acceleration, and force.
Strain gauges are passive transducers its electrical resistance will change when it is stretched or compressed and it uses the electrical resistance variation in wires to sense the strain produced by a force on the wire. If it is strained or stretched their resistance will change they consist of the long wire and are able to detect very small displacements produced by the applied force or pressure.
In photoelectric transducers when light is applied to it they produce voltage an example of a photoelectric transducer is cathode ray tube in which electrical signals will be converted into light energy
Linear variable differential transformer
A linear variable differential transformer is used to measure linear displacement it works on the principle of mutual inductance and it is one of the most popular types of displacement sensor LVDT is the transformer which consists of the primary and secondary coil. It can convert the displacement into a change in resistance.
Ultrasonic transducers can convert electrical signals to ultrasound waves and it can be used to measure the distance of sound based on reflection. Ultrasonic transducers can be used to find areas which are hard to find like high pressure or high-temperature areas these transducers use the ultrasonic or ultrasound waves to measure parameters like fluid level, flow rate…