Commonly used devices on the circuit board include: resistance, capacitance, diode, triode, thyristor, touch switch, liquid crystal, light-emitting diode, buzzer, various sensors, chips, relays and so on. And electronic components have different packaging types, different types of components have the same appearance, but the internal structure and use is very different, for example, TO220 packaging components may be triode, SCR, FET, or double diode. To-3 package components include triode, integrated circuit and so on. Diodes also come in several packages, glass, plastic and bolt packages, so how to identify them? Xiaobian and everyone together to see it.
Contour recognition method
Electronic component shape recognition is the physical object and the name should correspond, its purpose is to get an electronic component can know what it is, know its circuit graphic symbol.
Circuit graphic symbol recognition
Understanding the recognition information in circuit symbols is helpful to the memory of circuit symbols and the analysis of circuit working principle. The following points are mainly explained about the circuit graphic symbols of electronic components.
(1) The circuit graphic symbols of electronic components contain a lot of map recognition 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 polarity, there will be various expressions in the circuit graphic symbols.
(2) Component circuit graphic symbols have the characteristics of visualization, and each stroke or symbol of the circuit graphic symbol expresses specific map recognition information.
(3) The letter in the circuit symbol is the first letter of the word in English of the component. For example, T is used to represent Transformer, which is the first letter of Transformer in English. If you know professional English, it is also helpful to recognize the circuit symbol in the circuit diagram, which is very beneficial to some circuit diagram recognition.
Pin identification and pin polarity identification
The pins of many electronic components have polarity, and each pin can not be used instead of each other. At this time, it is necessary to identify the pins and the polarity of the pins through the circuit graphic symbol or the physical components.
Pin identification and pin polarity identification methods have two cases: one is the recognition of the circuit symbol, the other is the physical identification of electronic components.
The printing of the component itself
Generally speaking, the printed words express some parameters or models, of course, there are also the manufacturer's batch number, version number and other attributes, as well as some symbols of international certification. This method also depends on the usual understanding of component models and parameters. For example, for a triode-like device, labeled C1815 is a low-power low-frequency NPN triode; Label TL431 is integrated regulator IC; If labeled 13001, it is a low power switch tube, which can be used in small low power chargers.
Examples of electronic component identification
(1) CAPACITOR: C is the first letter of CAPACITOR. Capacitors can be divided into non-polar and polar according to polarity.
(2) Resistance: "R", the first letter of the English RESISTOR.
(3) Inductor: Inductor is made of insulated wire wound on the skeleton; Inductance is denoted by the letter "L". The value of the inductor is called the inductance quantity, and the unit is "Henry (H)". Due to the large size of the hyung units, the hao-hyung (mH) and wei-hyung (uH) are often used.
(4) transformer: transformer is a kind of inductor, voltage boost, step-down and isolation coupling, etc.; TRANSFORMER is represented by the letter "T" (the first letter of TRANSFORMER); Transformer has primary joint, secondary joint points, so in action must pay attention to.
(5) diode: diode with the letter "D", there are positive and negative points, not to plug back.
(6) Crystal oscillator: crystal oscillator, also known as crystal oscillator, is a quartz wafer that is processed by quartz crystal to generate resonance at a certain frequency, and is represented by "X" in English. Because the function of crystal oscillator is to stabilize the oscillation frequency, the important parameter of crystal oscillator is resonance frequency.