Surface Mount Resistor (SMD Resistor) is a Surface Mount Technology, SMT component, widely used in modern electronic devices. Unlike traditional lead resistors, chip resistors have no leads and can be directly soldered on the surface of the circuit board
1. Working principle of chip resistors:
The working principle of chip resistors is the same as that of ordinary resistor devices, that is, the resistance effect is generated by limiting the current. When current passes through the chip resistor, the current will be limited, thereby reducing the voltage in the circuit
The chip resistor plays an important role in modern electronic technology due to its small size, light weight, high precision, good stability and other characteristics. The main characteristics of the chip resistor are as follows:
① Miniaturization: The shape of the chip resistor is rectangular, the length and width are usually only a few millimeters, and the thickness is also very thin. It has the characteristics of small size, light weight, and high installation density, which can meet the needs of modern electronic equipment for miniaturization and lightweight
② High precision: The precision of SMD Resistor can reach 0.01%, 0.05%, 0.1%, 0.25%, etc., which meets the requirements of resistance precision in different application scenarios
High-precision chip resistors can ensure the stability and reliability of the circuit and improve the operating efficiency of the equipment
③ Good stability: The chip resistor is made of high-quality materials and advanced production technology, and has good stability. Under high temperature, high humidity, high pressure and other environments, the performance will not change significantly, ensuring the stable operation of the circuit
④ Good heat dissipation performance: Although the chip resistor is small in size, its heat dissipation area is relatively large, and it has good heat dissipation performance. When used in high-power circuits, it can effectively dissipate heat and prevent circuit damage caused by excessive temperature
⑤ Easy to install and maintain:
SMD resistors do not require complicated installation steps, they only need to be directly soldered on the surface of the circuit board, so installation, replacement and maintenance are very convenient
Due to their excellent characteristics, SMD resistors are used in almost all electronic equipment fields that require circuit regulation and control. The following are the main application ranges of SMD resistors:
Circuit application:
①Current limitation:
By connecting in series in the circuit, SMD resistors can be used to limit the current passing through the circuit to prevent excessive current from damaging other components
②Voltage division:
In the resistor voltage division circuit, SMD resistors cooperate with other resistors to change the voltage value at a certain point in the circuit according to Ohm's law to provide suitable working voltage for different electronic components
③Signal conditioning:
Used for signal attenuation, gain control, bias setting, etc., to ensure that the signal is within the appropriate range and improve signal quality
④Filtering function:
Combined with capacitors to form an RC filter, which is used to filter out AC noise or stabilize DC voltage in the circuit to improve signal stability and purity
⑤Timing and frequency response:
In the RC circuit, the RC time constant composed of SMD resistors and capacitors determines the response speed and frequency characteristics of the circuit
⑥ Matching network: In RF and microwave circuits, SMD resistors are used to create matching networks, adjust circuit impedance, achieve efficient signal transmission and reduce reflection
⑦ Temperature compensation: Resistors with specific temperature coefficients can be used to compensate for performance drift of other components in the circuit due to temperature changes
⑧ Power dissipation: It can be used as a load resistor to consume excess power and prevent circuit overload
⑨ Logic threshold setting: In digital circuits, SMD resistors can be combined with capacitors, transistors and other components to set logic threshold voltage
⑩ Protection function: In some circuits, SMD resistors can be used as overcurrent and overheating protection components. When the current or temperature exceeds the preset value, the circuit is cut off by heating or melting the resistor itself to protect other devices
Electronic equipment field:
①Mobile communication devices such as smart phones, tablets, and laptops. These devices use a large number of chip resistors for current regulation, signal processing and power control
②Communication equipment such as routers and switches, base station equipment, Wi-Fi modules, Bluetooth devices
③Medical equipment such as monitors, ultrasonic equipment, blood glucose meters, and blood pressure monitors
④Industrial control systems such as PLC (Programmable Logic Controller), sensor interfaces, and automation equipment
⑤Automotive electronics engine control unit (ECU), audio and video processing and other in-vehicle entertainment systems, ABS (anti-lock braking system), ESP (electronic stability program) and other safety systems
⑥Computers and data storage such as motherboards, hard drives and SSDs, graphics cards. From motherboards to various interface cards, chip resistors are used in circuit design to limit current, divide voltages, filter, etc.
⑦Household appliances such as televisions, refrigerators, and washing machines. Chip resistors ensure the stability and safety of the circuits in the circuit systems of these devices
