第1个回答 2011-02-18
中，英己送出
A transducer is a device that converts one type of energy to another. The conversion can be to/from electrical, electro-mechanical, electromagnetic, photonic, photovoltaic, or any other form of energy. While the term transducer commonly implies use as a sensor/detector, any device which converts energy can be considered a transducer.
Transducers are electric or electronic devices that transform energy from one manifestation into another. Most people, when they think of transducers, think specifically of devices that perform this transformation in order to gather or transfer information, but really, anything that converts energy can be considered a transducer.
Transducers that detect or transmit information include common items such as microphones, Geiger meters, potentiometers, pressure sensors, thermometers, and antennae. A microphone, for example, converts sound waves that strike its diaphragm into an analogous electrical signal that can be transmitted over wires. A pressure sensor turns the physical force being exerted on the sensing apparatus into an analog reading that can be easily represented. While many people think of transducers as being some sort of technical device, once you start looking for them, you will find transducers everywhere in your everyday life.
Most transducers have an inverse that allows for the energy to be returned to its original form. Audio cassettes, for example, are created by using a transducer to turn the electrical signal from the microphone pick-up – which in turn went through a transducer to convert the sound waves into electrical signal – into magnetic fluctuations on the tape head. These magnetic fluctuations are then read and converted by another transducer – in this case a stereo system – to be turned back into an electrical signal, which is then fed by wire to speakers, which act as yet another transducer to turn the electrical signal back into audio waves
Other transducers turn one type of energy into another form, not for the purpose of measuring something in the external environment or to communicate information, but rather to make use of that energy in a more productive manner. A light bulb, for example, one of the many transducers around us in our day-to-day lives, converts electrical energy into visible light. Electric motors are another common form of electromechanical transducer, converting electrical energy into kinetic energy to perform a mechanical task. The inverse of an electric motor – a generator – is also a transducer, turning kinetic energy into electrical energy that can then be used by other devices.
As in all energy conversions, some energy is lost when transducers operate. The efficiency of a transducer is found by comparing the total energy put into it to the total energy coming out of the system. Some transducers are very efficient, while others are extraordinarily inefficient. A radio antenna, for example, acts as a transducer to turn radio frequency power into an electromagnetic field; when operating well, this process is upwards of 80% efficient. Most electrical motors, by contrast, are well under 50% efficient, and a common light bulb, because of the amount of energy lost as heat, is less than 10% efficient.
What is the Difference Between Transducers and Sensors
Transducers are machines used to change one type of energy into another. They can often be found as a component of more complex devices. Sensors are explicitly intended to measure and express levels of measurement. Quite often, sensors are composed of transducers; therefore, one can see how easy it can be to confuse the two.
Generally, transducers come in basic varieties of which there are almost endless applications. The first variety is contact transducers. This type is categorized by a single point of contact used to detect energy. There is generally a coupling material, such as water or oil, employed in order to prevent distortion between the source of energy and the point of detection.
Many sensors utilize contact transducers in order to detect energy levels and convert that into an electrical energy which would then influence a display meter. One type of contact transducer that was almost ubiquitous in the late 1980s and early 1990s were tape heads. These were found in any cassette player, touching the magnetic tape and reading the magnetic information that was on it. This information was then converted to an electric signal that was carried by wire to speakers or headphones and then converted back into sound waves.
The second most common type of transducers is the immersion type. These are intended to work in liquid environments. This type is effective at measuring sound, pressure, or other forms of mechanical energy. Paintbrush transducers are used like immersion types are, but they work in open environments and have highly sensitive crystals to detect even the faintest levels of energy. Antennae for radio waves are paintbrush types as they collect the broadcast radio waves and convert them into electrical energy that is converted back into sound by a radio’s speakers.
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