Basic knowledge training of SMD electronic components

In all electronic circuits, our commonly used SMD electronic component include: SMD resistor, SMD capacitor, SMD

Diode, patch transistor, etc.

The four commonly used mainstream SMD component are explained. It can be used as a reference in daily applications.

One, SMD resistor

As the most commonly used device in circuits, SMD resistor are usually referred to as

resistance. The resistance is almost any

A non-carbonizable device in electronic circuits, as the name implies, electrical

The role of resistance is to hinder the role of electrons. The main work in the circuit

The rated power of the resistor should be replaced by 1.5~2 times the actual power

In order to ensure that the resistance is durable. Use a multimeter before inserting the resistor into the circuit

Ohm file to verify its resistance. When installing, make the type of resistance

Symbols such as value are easy to see, and the knight verifies.

Second, the SMD capacitor

SMD capacitor are also one of the most commonly used and most basic electronic component.

Used in the circuit for tuning, filtering, conversion, and side

Road, energy conversion and delay, etc. The replacement of SMD capacitor should consider the frequency and withstand voltage. electrolysis

The polarity of the capacitor should also be paid attention to, so that the + pole is connected to the DC high voltage

The use temperature should also be considered. The continuous working ring determined by the SMD capacitor design

Environmental temperature range. The range depends on its corresponding category

Temperature limit value, such as upper limit category temperature, lower limit category

Temperature, rated temperature (rated voltage can be applied continuously

The highest ambient temperature) and so on.

Three, SMD diode

The positive characteristics of the patch transistor: the first quadrant part of the characteristic curve, the curve

It has an exponential curve shape and is non-linear. Forward when the forward voltage is very low

The current is almost 0, this interval is called "dead zone

, The corresponding electricity

The voltage range is called the dead zone voltage or threshold voltage. The dead zone voltage of the germanium tube

The voltage is about 0.1V, and the dead zone voltage of the silicon tube is about 0.5V;

Reverse characteristics: the reverse current is very small, but when the reverse voltage is too high

When the PN junction breaks down, the reverse current increases sharply.

Four, SMD transistor

SMD transistor are classified according to structure, point contact type and surface contact type; according to working frequency

The rate is divided into high-frequency triode, injection triode, switch tube. According to power

Divided into high-power, medium-power, and low-power transistor. From the package form, there are

Metal package and plastic package and other forms. Due to the variety of transistor, in every

There are some specific models in the class, so they can be distinguished in advance when using

Negligence, otherwise the transistor will be damaged.