With the continuous miniaturization of electronic products,Chip resistorIt is widely used in various circuits because of its small size and stable performance. For electronic engineers and maintenance personnel, accurate reading of patchesresistanceThe resistance value is key to ensuring the normal operation of the circuit. This article will systematically introduce the relevant knowledge of chip resistor readings to help you quickly master the identification and measurement skills of chip resistors.
1. Overview of chip resistorsChip resistor (SMD resistor) is a surface mount component, usually manufactured using thick film or thin film processes. The resistance value is represented by the identification code on the surface of the resistor. Common identification methods include three-digit numbers, four-digit numbers, and letter codes. Due to their small size and non-polarity, chip resistors are widely used in modern electronic equipment.
2. How to read the identification code of chip resistors1. Three-digit identification method
The three-digit identification is the most common way to identify the resistance value of chip resistors. The first two digits represent significant figures, and the third digit represents the multiplication raised to the power of 10. For example, the designation "103" means 10×10³=10kΩ.
2. Four-digit identification method
The four-digit identification method is used for resistors with higher precision. The first three digits represent significant figures, and the last digit represents the power of 10 multiplied by. For example, "1001" means 100×10¹=1kΩ.
3. Letter code identification method
Some high-precision or special chip resistors use letter codes, such as "R" representing the decimal point. For example, "4R7" means 4.7Ω.
4. Color codes and other special marks
Although chip resistors are mainly identified by numbers, some models still use color codes or other special markings, which need to be identified in conjunction with the product manual.
3. Use a digital multimeter to measure the chip resistance1. Principles of power outage measurement
When measuring chip resistance, ensure that the circuit is powered off to avoid the influence of other components on the measurement results.
2. Select the appropriate measurement gear
Set the digital multimeter to the resistance range and select the appropriate range to obtain accurate readings.
3. Measurement method
Use the test pen to lightly touch both ends of the chip resistor, keep it steady, and read the resistance value on the display.
4. Pay attention to measurement errors
Due to the small size of chip resistors, poor contact or parallel connection of other components in the circuit may cause reading deviations. Multiple measurements should be made and judged based on the identification code.
4. Tolerance and power parameters of chip resistors1. Tolerance understanding
Chip resistors are usually marked with tolerance ranges such as ±1% and ±5%, which represent the possible error range of the actual resistance value.
2. Power specifications
Select chip resistors with appropriate power levels according to circuit requirements. Common specifications include 1/8W, 1/4W and other specifications. Too small power can easily cause component damage.
5. Common specifications and sizes of chip resistorsChip resistors come in a variety of package sizes, such as 0402, 0603, 0805, etc. The smaller the size, the lower the power. Understanding the dimensional specifications will help you correctly identify and replace chip resistors.
6. Precautions and practical skills1. Use a magnifying glass to help identify the identification code of the small size chip resistor.
2. For chip resistors that cannot be accurately read, inference can be made by combining the circuit diagram and measurement data.
3. Keep the test pen clean to prevent stains from affecting the measurement.
4. In high-frequency circuits, the parasitic parameters of chip resistors also need to be considered to avoid affecting circuit performance.
Chip resistors are an indispensable component in modern electronic equipment, and accurate reading of their resistance is crucial for circuit design, maintenance and debugging. By mastering the identification code reading method of chip resistors, the correct use of digital multimeter measurement techniques, and combined with the understanding of tolerance and power parameters, you can effectively improve work efficiency and ensure the stable operation of electronic products. I hope the content of this article can help you fully understand the core knowledge of chip resistance readings and become an expert in the electronics field.
