Čo's nesprávne s the digital multimeter obrazovka mať a digitálny zobraziť funkcia a nie byť schopný použiť to
Tam sú všeobecne dve možnosti pre toto situácia na nastať. Po prvé, tam je a porucha v vstup kanál z the sonda and nameraný parameter, spôsobujúci the analógovo-digitálny prevodník v the multimeter na be neschopný na čítať the signal; the second issue is the internal analog-to-digital converter of the multimeter is damaged. Let's introduce these two situations oddelene.
1. Rýchly úsudok z kvalita z a multimeter analógovo-digitálny prevodník:
The questioner said that the display screen has a display and the function is unusable. If the data displayed on the display screen is disorganized and a multimeter is used to measure parameters such as voltage and resistance, the numbers displayed on the multimeter will not change. At this point, we need to suspect whether the analog-to-digital converter inside is faulty. Here, with the normal 3 ½ Taking ICL7106, a commonly used analog-to-digital converter for a digital multimeter, as an example, to introduce the quick judgment of the quality of analog-to-digital converters. As shown in the above figure, it is a 200mV DC voltmeter composed of ICL7106. During normal operation, there is a stable voltage of 2.8-3.0V between the V plus terminal (pin 1) and COM terminal (pin 32) of ICL7106, and this voltage does not change with the battery voltage of the multimeter. Therefore, we only need to use another multimeter to measure the voltage between pin 1 and pin 32 of ICL7106 to see if it is the above value. If the measured voltage deviates significantly from the above voltage, Basically, it can be determined that there is a problem with the analog-to-digital converter or its peripheral components. At this point, you can first check the external components of ICL7106, and then determine if the multimeter is damaged.
2. Diagnóza of multimeter sonda a vstup kanál poruchy
Po potvrdení že tam je nie problém s analógovo-digitálny prevodník of the digital multimeter, you can first adjust the range switch to the DC 20}0mV position to see if the number display on the display screen is "000.0", and then adjust it to the odpor poloha to zobrazené is "1". If you rotate the range switch and the zobrazené číslo zmeny, it znamená to vnútorný drôt z sonda je zlomený. At toto čas, vy môžem použiť the odpor alebo bzučiak rozsah na určiť ktorý sonda je chybný. In sčítanie, tam je a poistka v vstup terminál z z the prúd rozsah of 200mA a pod zapnutý the digitálny multimeter. If toto poistka horí out, it bude príčina the prúd rozsah na na be nepoužiteľné.
