Will digital multimeters replace analog analog multimeters?
In addition to the different display methods, there is another biggest difference between the two, that is, the internal resistance is different. The internal resistance of the digital multimeter is more than two orders of magnitude higher than that of the pointer multimeter. The internal resistance of the best pointer meter is not as good as that of the worst The internal resistance of the digital meter is high. This is one of the reasons why digital meters are more accurate than pointer meters.
However, high internal resistance is not necessarily an advantage sometimes. For example, when measuring resistance, the multimeter must provide current to flow through the resistance in order to obtain the resistance value by measuring the resistance voltage. At this time, the current provided by the digital meter is often very small. It is at the microampere level, and the pointer meter is at the milliampere level. If you use a resistance file to measure the leakage resistance of the capacitor, the current of the digital meter is too slow to fully charge the microfarad level capacitor, and it is almost impossible to measure. The pointer meter can quickly fully charge the capacitor and detect the leakage.
However, the small output current characteristic of the digital meter is convenient and accurate when measuring the resistance value online. Because the output current is small, the surrounding online capacitance, inductance, transistor and so on, the shunt is very small, so the online measurement of resistance The resistance value is relatively accurate and saves trouble. Generally, you can measure whether the resistance value of the resistance is normal without soldering the solder joints.
Another example is to measure the quality of the PN junction of a nonlinear device. The current provided by the digital meter is often quite different from the actual working current, and the judgment will not be very accurate. At this time, the pointer table is very useful.
Two kinds of measurement tools, the digital meter can replace the pointer meter more in the production measurement and control link. However, in the fields of technology development and maintenance, pointer watches still play an irreplaceable role.
