A transducer is a device that converts energy from one form to another. Usually a transducer converts a signal in one form of energy to a signal in another. [1] Transducers are often employed at the boundaries of automation, measurement, and control systems, where electrical signals are converted to and from other physical quantities (energy, force, torque, light, motion, position, etc.). The process of converting one form of energy to another is known as transduction. [2]
Transducers can be categorized by which direction information passes through them:
Passive transducers require an external power source to operate, which is called an excitation signal. The signal is modulated by the sensor to produce an output signal. For example, a thermistor does not generate any electrical signal, but by passing an electric current through it, its resistance can be measured by detecting variations in the current or voltage across the thermistor. [5] [2]
Active transducers in contrast, generate electric current in response to an external stimulus which serves as the output signal without the need of an additional energy source. Such examples are a photodiode, and a piezoelectric sensor, photovoltic, thermocouple. [5]
Some specifications that are used to rate transducers:
Electromechanical input feeds meters and sensors, while electromechanical output devices are generically called actuators ):
Also known as photoelectric:
A thermocouple, also known as a "thermoelectrical thermometer", is an electrical device consisting of two dissimilar electrical conductors forming an electrical junction. A thermocouple produces a temperature-dependent voltage as a result of the Seebeck effect, and this voltage can be interpreted to measure temperature. Thermocouples are widely used as temperature sensors.
A microphone, colloquially called a mic, or mike, is a transducer that converts sound into an electrical signal. Microphones are used in many applications such as telephones, hearing aids, public address systems for concert halls and public events, motion picture production, live and recorded audio engineering, sound recording, two-way radios, megaphones, and radio and television broadcasting. They are also used in computers and other electronic devices, such as mobile phones, for recording sounds, speech recognition, VoIP, and other purposes, such as ultrasonic sensors or knock sensors.
Data acquisition is the process of sampling signals that measure real-world physical conditions and converting the resulting samples into digital numeric values that can be manipulated by a computer. Data acquisition systems, abbreviated by the acronyms DAS,DAQ, or DAU, typically convert analog waveforms into digital values for processing. The components of data acquisition systems include:
A thermostat is a regulating device component which senses the temperature of a physical system and performs actions so that the system's temperature is maintained near a desired setpoint.
Signal refers to both the process and the result of transmission of data over some media accomplished by embedding some variation. Signals are important in multiple subject fields including signal processing, information theory and biology.
An actuator is a component of a machine that produces force, torque, or displacement, usually in a controlled way, when an electrical, pneumatic or hydraulic input is supplied to it in a system. An actuator converts such an input signal into the required form of mechanical energy. It is a type of transducer. In simple terms, it is a "mover".
A thermopile is an electronic device that converts thermal energy into electrical energy. It is composed of several thermocouples connected usually in series or, less commonly, in parallel. Such a device works on the principle of the thermoelectric effect, i.e., generating a voltage when its dissimilar metals (thermocouples) are exposed to a temperature difference.
A pickup is a transducer that captures or senses mechanical vibrations produced by musical instruments, particularly stringed instruments such as the electric guitar, and converts these to an electrical signal that is amplified using an instrument amplifier to produce musical sounds through a loudspeaker in a speaker enclosure. The signal from a pickup can also be recorded directly.
Energy harvesting (EH) – also known as power harvesting,energy scavenging, or ambient power – is the process by which energy is derived from external sources, then stored for use by small, wireless autonomous devices, like those used in wearable electronics, condition monitoring, and wireless sensor networks.
A piezoelectric motor or piezo motor is a type of electric motor based on the change in shape of a piezoelectric material when an electric field is applied, as a consequence of the converse piezoelectric effect. An electrical circuit makes acoustic or ultrasonic vibrations in the piezoelectric material, most often lead zirconate titanate and occasionally lithium niobate or other single-crystal materials, which can produce linear or rotary motion depending on their mechanism. Examples of types of piezoelectric motors include inchworm motors, stepper and slip-stick motors as well as ultrasonic motors which can be further categorized into standing wave and travelling wave motors. Piezoelectric motors typically use a cyclic stepping motion, which allows the oscillation of the crystals to produce an arbitrarily large motion, as opposed to most other piezoelectric actuators where the range of motion is limited by the static strain that may be induced in the piezoelectric element.
An electronic component is any basic discrete electronic device or physical entity part of an electronic system used to affect electrons or their associated fields. Electronic components are mostly industrial products, available in a singular form and are not to be confused with electrical elements, which are conceptual abstractions representing idealized electronic components and elements. A datasheet for an electronic component is a technical document that provides detailed information about the component's specifications, characteristics, and performance.
Level sensors detect the level of liquids and other fluids and fluidized solids, including slurries, granular materials, and powders that exhibit an upper free surface. Substances that flow become essentially horizontal in their containers because of gravity whereas most bulk solids pile at an angle of repose to a peak. The substance to be measured can be inside a container or can be in its natural form. The level measurement can be either continuous or point values. Continuous level sensors measure level within a specified range and determine the exact amount of substance in a certain place, while point-level sensors only indicate whether the substance is above or below the sensing point. Generally the latter detect levels that are excessively high or low.
In electronics and signal processing, signal conditioning is the manipulation of an analog signal in such a way that it meets the requirements of the next stage for further processing.
Ultrasonic transducers and ultrasonic sensors are devices that generate or sense ultrasound energy. They can be divided into three broad categories: transmitters, receivers and transceivers. Transmitters convert electrical signals into ultrasound, receivers convert ultrasound into electrical signals, and transceivers can both transmit and receive ultrasound.
Electronic Diesel Control is a diesel engine fuel injection control system for the precise metering and delivery of fuel into the combustion chamber of modern diesel engines used in trucks and cars.
A MEMS magnetic actuator is a device that uses the microelectromechanical systems (MEMS) to convert an electric current into a mechanical output by employing the well-known Lorentz Force Equation or the theory of Magnetism.
Surface acoustic wave sensors are a class of microelectromechanical systems (MEMS) which rely on the modulation of surface acoustic waves to sense a physical phenomenon. The sensor transduces an input electrical signal into a mechanical wave which, unlike an electrical signal, can be easily influenced by physical phenomena. The device then transduces this wave back into an electrical signal. Changes in amplitude, phase, frequency, or time-delay between the input and output electrical signals can be used to measure the presence of the desired phenomenon.
In control system theory, and various branches of engineering, a transfer function matrix, or just transfer matrix is a generalisation of the transfer functions of single-input single-output (SISO) systems to multiple-input and multiple-output (MIMO) systems. The matrix relates the outputs of the system to its inputs. It is a particularly useful construction for linear time-invariant (LTI) systems because it can be expressed in terms of the s-plane.
This glossary of electrical and electronics engineering is a list of definitions of terms and concepts related specifically to electrical engineering and electronics engineering. For terms related to engineering in general, see Glossary of engineering.
