Mga Tipo sa Transducer

Transducers: Definition, Functions, and Classification

Ang transducer usa ka elektronikong device nga nagpalya og dako nga papel sa pag-convert sa pisikal nga kantidad ngadto sa electrical signals. Adunay duha ka fundamental nga functions: sensing ug transduction. Unang, adunay siya'y detection sa pisikal nga kantidad nga interesado, sama sa temperature, pressure, o displacement. Pagkatapos, iya gyud ang pag-transform sa kantidad nga fisikal ngadto sa mechanical work o, mas common, sa electrical signal nga makakitaan, processed, ug analyzed.

Ang mga transducer adunay wide variety nga types ug mahimong ikategoryahan batas sa several distinct criteria:

• Based on the Transduction Mechanism Employed: Kini nga classification focus sa specific physical or chemical processes diin ang transducer mogamit sa pag-convert sa input pisikal nga kantidad ngadto sa electrical output. Ang iba't ibang transduction mechanisms gibag-o sa iba't ibang types of measurements ug applications, enabling precise ug reliable sensing across a broad spectrum of physical phenomena.

• As Primary and Secondary Transducers: Ang primary transducer direkta ang mag-convert sa gisukdan nga pisikal nga kantidad ngadto sa electrical signal. Sa uban, ang secondary transducer nagtrabaho sa pakigbatok sa primary transducer, padayon nga modifying o processing sa electrical signal nga giproduce sa primary device aron mapadako ang usability o accuracy.

• As Passive and Active Transducers: Ang passive transducers gi-depende sa external power source aron mokarga ug produce an output signal nga function sa input pisikal nga kantidad ug applied power. Ang active transducers, sa uban, adunay ilang own power source ug makaproduce og output signal wala na dependi sa external power supply, often providing greater sensitivity ug signal strength.

• As Analogue and Digital Transducers: Ang analogue transducers produce an output signal nga varies continuously sa input pisikal nga kantidad, typically in the form of a voltage or current. Ang digital transducers, sa uban, convert the input quantity into a discrete digital signal, which is easier to process, store, ug transmit using modern digital electronics ug computing systems.

• As Transducers and Inverse Transducers: Ang standard transducer converts a physical quantity into an electrical signal. Ang inverse transducer, conversely, takes an electrical signal as input ug converts it back into a physical quantity, effectively reversing the process of a traditional transducer. This concept is useful in applications where electrical control is required to generate a specific physical response.

Sa operation, ang transducer receives the measurand—the pisikal nga kantidad nga gisukdan—and produces an output signal nga proportional sa magnitude sa input. Kini nga output signal pagkatapos matransmit sa a signal conditioning device. Hini, ang signal undergoes a series of processes, including attenuation (adjusting the signal's amplitude), filtering (removing unwanted noise or frequencies), ug modulation (encoding the signal for better transmission or processing). These steps ensure that the final signal is in an optimal form for subsequent analysis, display, or control operations.

Ang input quantity of a transducer is typically a non - electrical quantity, while the output electrical signal can be in the form of current, voltage, or frequency.

1. Classification based on the Principle of Transduction

Ang mga transducer mahimong ikategoryahan batas sa transduction medium nga gi-utilize. Ang transduction medium mahimong resistive, inductive, o capacitive. Kini nga classification determined sa conversion process diin ang input transducer transforms the input signal into resistance, inductance, o capacitance respectively. Each type of transduction medium adunay iyang own unique characteristics ug suitable for different measurement applications, enabling the accurate conversion of various physical quantities into electrical signals.

2. Primary and Secondary Transducers

• Primary Transducer
  Ang transducer often comprises both mechanical ug electrical components. Ang mechanical part sa transducer responsible sa pag-convert sa physical input quantities into a mechanical signal. Kini nga mechanical component referred as the primary transducer. It acts as the initial sensing element, directly interacting with the physical quantity being measured, such as pressure, temperature, or displacement, ug converting it into a mechanical form nga makakitaan further processing.

• Secondary Transducer
  Ang secondary transducer takes the mechanical signal generated by the primary transducer ug converts it into an electrical signal. Ang magnitude sa output electrical signal directly related sa characteristics sa input mechanical signal. In this way, ang secondary transducer bridges the gap between the mechanical ug electrical domains, making it possible to measure ug analyze the original physical quantity using electrical measurement ug processing techniques.

Example of Primary and Secondary Transducers

Take the Bourdon's Tube, as illustrated in the figure below, as an example. Ang Bourdon's Tube functions as a primary transducer. Iya designed to detect pressure ug convert it into a displacement at its free end. When pressure is applied to the tube, its shape deforms, causing the free end to move. This displacement then acts as the input to the next stage of the system.

The movement of the free end of the Bourdon's Tube causes the core of a Linear Variable Displacement Transformer (LVDT) to shift. As the core moves within the LVDT, it induces an output voltage. This induced voltage is directly proportional to the displacement of the tube's free end, ug consequently, to the original pressure applied to the Bourdon's Tube.

In the case of the Bourdon's Tube - LVDT system, two distinct transduction processes occur. First, the primary transduction takes place when the Bourdon's Tube converts pressure into displacement. Then, the secondary transduction occurs as the LVDT converts this displacement into an electrical voltage signal. This example clearly demonstrates how primary ug secondary transducers work in tandem to accurately measure ug convert a physical quantity into an electrical output for further analysis ug use.

The Bourdon's Tube serves as the primary transducer, while the L.V.D.T. (Linear Variable Displacement Transformer) functions as the secondary transducer.

3. Passive and Active Transducers

Ang mga transducer mahimong ikategoryahan into active ug passive types, each with distinct operational characteristics.

Passive Transducers

A passive transducer is one that relies on an external power supply to operate, which is why it is also referred to as an externally - powered transducer. Capacitive, resistive, ug inductive transducers are typical examples of passive transducers. These transducers work by modifying an electrical property (such as resistance, capacitance, or inductance) in response to the input physical quantity. However, they do not generate their own electrical energy; instead, they require an external source of power to produce a measurable output signal nga reflects the change in the physical quantity being measured.

Active Transducers

In contrast, an active transducer does not necessitate an external power source for operation. These transducers are self - generating, meaning they can produce their own voltage or current output. The output signal of an active transducer is directly derived from the input physical quantity. Active transducers are capable of converting various physical phenomena, such as velocity, temperature, force, ug light intensity, into electrical signals without relying on an external power input. Examples of active transducers include piezoelectric crystals, photovoltaic cells, tachogenerators, ug thermocouples.

Example: Piezoelectric Crystal

To illustrate the operation of an active transducer, consider a piezoelectric crystal. A piezoelectric crystal is typically sandwiched between two metallic electrodes, ug the entire assembly is securely fastened to a base. A mass is then placed on top of this sandwiched structure.

Piezoelectric crystals possess a unique property: when a force is applied to them, they generate an electric voltage. In the described setup, the base can experience acceleration, which causes the mass to exert a force on the crystal. This force, in turn, induces an output voltage across the crystal. The magnitude of this output voltage is directly proportional to the acceleration experienced by the base, effectively converting mechanical acceleration into an electrical signal. This example clearly demonstrates how active transducers can self - generate electrical outputs based on physical inputs, highlighting their distinct functionality compared to passive transducers.

The transducer mentioned above is known as an accelerometer, which is designed to convert acceleration into an electric voltage. Notably, this type of transducer operates without the need for any auxiliary power source during the conversion of the physical quantity into an electrical signal, showcasing its self - sufficient nature in signal generation.

4. Analog and Digital Transducers

Ang mga transducer mahimong ikategoryahan based on the nature of their output signals, which can be either continuous or discrete.

Analog Transducers

An analog transducer transforms the input quantity into a continuous function. This means that the output signal varies smoothly ug continuously in response to changes in the input. Examples of analog transducers include strain gauges, Linear Variable Displacement Transformers (LVDTs), thermocouples, ug thermistors. These devices are widely used in various applications where a proportional ug continuous representation of the measured physical quantity is required, such as in precision measurement systems ug industrial process control.

Digital Transducers

Digital transducers, sa uban, convert the input quantity into a digital signal, typically in the form of pulses. Digital signals operate based on binary states, representing information as either "high" or "low" power levels. This digital output format offers several advantages, including enhanced noise immunity, easier integration with digital electronics ug computing systems, ug more straightforward data processing ug storage. Digital transducers are increasingly being adopted in modern measurement ug control systems due to the prevalence of digital technologies.

5. Transducers and Inverse Transducers

Transducers

A transducer is defined as a device that converts non - electrical quantities into electrical quantities. This conversion process enables the measurement, monitoring, ug control of various physical phenomena, such as temperature, pressure, displacement, ug force, using electrical measurement ug processing techniques. Transducers play a crucial role in a wide range of applications, from industrial automation to scientific research ug consumer electronics.

Inverse Transducers

Inverse transducers perform the opposite function of traditional transducers. They convert electrical quantities back into physical quantities. These transducers typically have a high electrical input ug a corresponding low non - electrical output. Inverse transducers are used in applications where electrical signals need to be translated into physical actions or responses, such as in certain types of actuators ug control systems. The concept of inverse transducers provides a means to close the loop between electrical control ug physical operation, facilitating more complex ug precise control of mechanical ug physical systems.