We know that everything has its own life, and resistance is no exception. When we choose a resistor, we usually look at the service life to determine the stability of the resistor. In fact, we only know this unilaterally. If we further understand, we will find that the resistor has two kinds of load life and shelf life.


First, the load life analysis of the resistance
The so-called resistive load life is actually related to the three factors that affect the resistance, namely the power, temperature and time of use of the resistor. The active period of resistance change is several hundred hours before use, and the longer it is, the more stable it will become. This is because the resistance element itself tends to be stable over time, or the stress between the resistance element and the substrate is gradually released. The index of resistive load life can only be monitored by sampling test, because this test requires at least 1,000 hours, and aerospace applications may require up to 10,000 hours of testing, and this test is a destructive experiment.

Second, the shelf life of the resistor
The so-called resistance shelf life actually refers to the resistance stability under storage conditions. The shelf life of the resistor is the same as the load life. The longer the resistor is stored, the more the resistance changes. Usually, some precision instruments are used in precision equipment. They are not used immediately, but are stored for some time. This has a lot to do with resistance.
Therefore, for the resistance of the old batch, as long as the accuracy is within the nominal value, and the solder fillet is not oxidized, its stability is better than the resistance of the new batch. The storage of the resistors must pay special attention to the humidity control, and the humidity will have a great influence on the resistance of any resistor.

 For precision resistors, its load life and shelf life are very important. On many high-end equipment, the purchase of precision resistors generally depends on the production date, and some require older date requirements.
Because of the aging of such precision resistors, the resistance tends to be stable. In addition, we use the resistor to reduce the value of the resistance when using the resistor, which can also extend the life of the resistor.