Commonly used devices on circuit boards include: resistors, capacitors, diodes, triodes, thyristors, tact switches, liquid crystals, light-emitting diodes, buzzers, various sensors, chips, relays, etc.
Moreover, electronic components have different packaging types. Different types of components have the same shape, but their internal structures and uses are very different. For example, the components packaged in TO220 may be triodes, thyristors, field effect transistors, or double diodes. The components of TO-3 package include transistors, integrated circuits, etc. Diodes also have several packages, glass package, plastic package and bolt package, so how to identify them? Let’s take a look with you.
1. Appearance recognition method
The shape recognition of electronic components is the correspondence between the physical object and the name. The purpose is to get an electronic component to know what it is and its circuit graphic symbol.
2. Recognition of circuit graphic symbols
Understanding the identification information in the circuit graphic symbols is helpful for the memory of the circuit symbols, and is also very beneficial for the analysis of the working principle of the circuit. The following points are mainly explained about the identification of circuit graphic symbols of electronic components.
(1) The circuit graphic symbols of electronic components contain a lot of identification information for circuit analysis. The most basic thing is to know how many pins the component has through the circuit graphic symbols. If the pins have positive and negative polarities, There are also various expressions in circuit graphic symbols.
(2) The circuit graphic symbols of components have the characteristics of visualization, and each stroke or symbol of the circuit graphic symbols expresses specific identification information.
(3) The letter of the circuit graphic symbol is the first letter of the English word of the component. For example, the transformer is represented by T, which is the first letter of the English Transformer. If you know professional English, it will also help to identify the circuit graphic symbols of the circuit diagram, which is very beneficial for the recognition of some circuits.
3. Pin identification and pin polarity identification
The pins of many electronic components have polarities, and the pins cannot be substituted for each other. At this time, it is necessary to identify the pins and the polarity of the pins through circuit graphic symbols or physical components.
There are two types of pin identification and pin polarity identification methods: one is the identification of circuit graphic symbols, and the other is the physical identification of electronic components.
4. The printing of the components themselves
Generally speaking, printing expresses certain parameters or models. Of course, there are also attributes such as the manufacturer's batch number and version number. Some international certification symbols are also available. This method also depends on the usual understanding of component models and parameters. For example, a transistor-like device, marked C1815, is a low-power low-frequency NPN transistor; marked TL431 is an integrated voltage regulator IC; if marked 13001, it is a low-power switching tube, which can be used in small and low-power chargers.
5. Examples of electronic component identification
(1) Capacitor: represented by "C", which is the first letter of the English CAPACITOR. Capacitors can be divided into non-polar and polar based on polarity.
(2) Resistance: represented by "R", which is the first letter of English RESISTOR.
(3) Inductor: The inductance is wound with insulated wire on the skeleton; the inductance is represented by the letter "L". The value of the inductor is called the inductance, and the unit is "Henry (H)"; because the unit of "Henry" is too large, "millihenry (mH)" and "microhenry (uH)" are often used.
(4) Transformer: The transformer is a kind of inductive device, which is divided into step-up, step-down and isolation coupling; the transformer is represented by the letter "T" (the first letter of the English TRANSFORMER); the transformer has primary connectors, secondary It is divided into grade joints, so attention must be paid when acting.
(5) Diode: The diode is represented by the letter "D", which is divided into positive and negative electrodes, and is not inserted in reverse.
(6) Crystal oscillator: Crystal oscillator, also known as crystal oscillator, is a quartz crystal that is processed into a quartz crystal that resonates at a certain frequency, and is represented by the English word "X". Since the function of the crystal oscillator is to stabilize the oscillation frequency, the important parameter of the crystal oscillator is the resonant frequency.
The above is the relevant answer on how to identify the components on the circuit board. I hope it will be helpful to everyone. Lansheng Technology welcomes friends who need electronic components to come and consult~