Detection of damage to fixed resistors
In the detection of fixed resistors, the resistance can be measured accurately through direct measurement with a multimeter, from which it can be judged whether the resistance has a fault. Although there is no skill at all, it is worth noting that in order to ensure the accuracy of the measured value, you need to select the range according to the measurement needs, and try to control the reading as accurately as possible. In this regard, due to the non-linear relationship of the ohm scale, in order to improve accuracy, everyone must also try to control the pointer to the middle position of the dial, in order to make the measurement more accurate and avoid errors affecting the judgment. Generally speaking, if the measured value and the actual value are only within a maximum of 20% of the error, then the resistance is normal, if it exceeds this range, it means that the resistance has been damaged.
Thermistor damage detection
In the detection work of the thermistor, the method of temperature change is usually used to assist the detection. Taking the thermistor with a positive coefficient as an example, during the detection, first measure the heat with the R×1 block of the multimeter at normal temperature The actual resistance value of the varistor can be used for preliminary damage detection by comparing this resistance value with the approved value. However, it should be noted that in order to ensure that the resistance does not have other faults, you need to carry out further testing under heating. Generally speaking, when the positive temperature thermistor works normally, its resistance value will increase with the rise of temperature. To ensure that this function is normal, you should observe the resistance value change when heating the resistor and judge the sensitivity of the thermistor. Happening. To determine the working condition of the thermistor, the above two steps are essential.
Detection of photoresistor damage
Finally, let's take a look at the detection method of the photoresistor. For the photoresistor, to ensure the smoothness of the detection work, you need to first cover the light-transmitting port of the resistor with an opaque material. Under normal circumstances, At this time, when the resistance measurement is performed, the resistance value does not change, and the resistance value should be close to infinity. If not, then the photoresistor has been damaged. In addition, in the further confirmation, you need to observe the change of resistance through the stimulation of the light source. If the resistance is obviously reduced when the light source is not available, it also indicates that the resistance has been damaged. The detection of these two aspects is a necessary process. Only when all are guaranteed can the working condition of the resistor be explained.