How to Test Chip Resistors? SMD Resistors Supplier

 In the debugging and repair of electronic circuits, accurate testing of chip resistors is an essential skill. Chip resistors may be small, but it depends on whether the whole circuit can operate properly. Today, MobikeChip will explain in detail how to test chip resistors.

 Appearance Inspection: Initial Hidden Danger Detection

The appearance of the chip resistor can reveal a lot of key information, to open the road to testing, the first thing to do is to carry out a detailed examination of its appearance. Normal chip resistors, the surface should be flat and smooth, without obvious physical damage, such as burn marks, cracking, discoloration. If the resistor surface is found to have black spots or signs of burning, this likely means that the resistor has been damaged by the excessive current it has withstood in the course of its work, at which time the resistance value of the resistor is likely to have undergone abnormal changes and cannot function properly.

At the same time, pay attention to the clarity of the resistor's logo. Chip resistors are usually printed resistance and other markings, if the markings are blurred or even completely worn out, on the one hand, may cause difficulties for the subsequent test judgment, on the other hand, also implies that the resistor may have experienced high temperatures, friction and other adverse conditions, the stability of its performance is in doubt. In addition, the status of the solder joints should not be ignored, to see whether the resistor pins and circuit board weld points are firm, rounded, there is no false welding, desoldering phenomenon. The soldering may lead to poor contact with the resistor, so that the circuit has intermittent failures; desoldering is directly out of the circuit, the resistor loses its role. Through the appearance of the inspection, we can quickly rule out some of the physical damage or welding problems caused by the hidden faults, to lay the foundation for subsequent accurate testing.

the multimeter measurement: accurate judgment of resistance value

Multimeter is the core tool for testing chip resistors. Before operation, make sure the multimeter is fully charged, functioning properly, and set its range knob to the resistance measurement gear. According to the approximate range of nominal resistance value of chip resistors, select the appropriate range, try to let the measured value in the middle of the range, in order to protect the measurement accuracy. For example, to estimate the resistance value in tens of ohms to hundreds of ohms, you can choose 200Ω or 2kΩ range gear.

When measuring, if conditions permit, it is best to remove the chip resistor from the circuit board carefully to avoid other parallel or series components to interfere with the measurement results. If it is not convenient to remove, be sure to confirm the connection relationship between the resistor and the surrounding components to ensure that the measurement is a single resistor resistance value. The two pens of the multimeter will be lightly touch the two pins of the resistor, at this time, the multimeter display will show a value, this value is the resistance value of the chip resistor measured. It should be noted that, due to the existence of a certain precision error resistor, the actual measured value and the nominal value of a slight deviation is normal, as long as the nominal accuracy of the resistor within the scope of the resistor can be judged as basically normal resistance. For example, a nominal value of 100Ω, precision ±5% of the resistance, the actual measured value between 95Ω and 105Ω, can be regarded as qualified. If the measured value is infinity, indicating that the resistor is open, can not conduct electricity; if much smaller than the nominal value or even close to zero, there may be a short-circuit situation, the resistor can not work properly.

the circuit function test: comprehensive verification of performance

Simple resistance measurement is sometimes not enough to determine the chip resistor in the circuit of the working state, to carry out circuit function test can provide us with a more comprehensive basis for judgment. The circuit board containing the chip resistor to be tested will be connected to the normal operation of the circuit system, to observe whether the circuit can achieve the expected function.

In a simple LED lighting circuit, for example, if the chip resistor is used as a current limiter, the LEDs should normally emit light steadily and at a moderate brightness. If there is a problem with the resistor, it may cause the LED not to light up (resistor open circuit, current can not pass through), too bright (resistor short circuit, current is too high) or even damaged. Another example is in a voltage divider circuit, by monitoring the voltage value of the voltage divider node is in line with the design requirements, but also can be reversed to deduce the operating state of the chip resistor. When testing the functionality of a circuit, combining the results of previous visual inspections and multimeter measurements can more accurately determine whether a chip resistor is functioning properly and how it affects the performance of the circuit as a whole.  

At MobikeChip, we not only provide high quality chip resistor products, but also dedicate ourselves to teaching you professional electronic component knowledge and testing skills. Mastering how to test chip resistors will help you in your electronic design, debugging and maintenance journey. If you encounter problems in testing, selecting or applying chip resistors, please feel free to visit MobikeChip's website, and our professional team will be happy to answer your questions.