Things you may not know about digital multimeters!
As a measuring instrument that replaces the electroscope pen used by electricians in the early days, I believe that the majority of electricians must have used it. The multimeter is an instrument that integrates AC/DC voltage, current, resistance (the on-off detection function is an extension of the resistance measurement function), and many other measurement functions. big help. Due to the advantages of small size, light weight, intuitive and convenient reading, and high measurement accuracy, various types of digital multimeters have become standard equipment for the majority of electricians (the classic models include DT920X, VC97 series, etc.). Today, I will learn some knowledge about digital multimeters that I have collected and sorted out with my friends.
1. When purchasing a digital multimeter, we'd better choose those products with the "AUTO POWER OFF (automatic shutdown)" function. In this way, the waste of power caused by forgetting to turn off the machine during use can be prevented, and the service life of the liquid crystal display screen can be extended.
2. If possible, when performing on-off measurement, try not to use gears with high power consumption and buzzing functions. Instead, you can use diodes or resistance gears with the same function. According to my personal test, the difference between the battery life of the multimeter in the two cases is nearly doubled!
3. When the "low battery" prompt appears on the multimeter, everyone should take the time to replace the battery. Otherwise, while affecting the measurement accuracy, some power management circuits inside the multimeter will be "locked" and the multimeter cannot be turned on normally! I have scrapped two expensive multimeters because of this, and I have a deep understanding!
4. In the process of using the multimeter, everyone should use moderate force when flipping the gear switch, and avoid sparks all the way with lightning bolts! This is because most (especially the popular version of electrical measuring multimeters) multimeter gear conversion is realized by different combinations of the lower copper sheet of the gear switch and the reserved copper foil on the internal PCB printed circuit board. Uninterrupted toggling the gear switch will inevitably increase the wear between the copper sheet and the copper foil, which will affect the measurement accuracy (contact resistance) and greatly shorten the service life of the multimeter! One of my quick-tempered colleagues did not pay attention to this detail, and as a result set a record of breaking three multimeters in one year!
