Will digital multimeters replace analog pointer multimeters?
The biggest difference between the two is not only the display method, but also the internal resistance. The internal resistance of a digital multimeter is more than two orders of magnitude higher than that of a pointer multimeter. Even the best pointer multimeter has a lower internal resistance than the worst digital multimeter. This is also one of the reasons why digital meters measure more accurately than analog meters.
However, high internal resistance may not necessarily be an advantage. For example, when measuring resistance, a multimeter must provide current flowing through the resistance in order to obtain the resistance value by measuring the resistance voltage. At this time, a digital meter often provides a very small current, which is in the microampere level, while a pointer meter is in the milliampere level. If you use the resistance range to measure the leakage resistance of a capacitor, the current of a digital meter at this point is too slow to fully charge the microcampere level capacitor, making it almost impossible to measure, while a pointer meter can quickly charge the capacitor and measure whether there is leakage.
However, the small output current feature of a digital meter is convenient, accurate, and unique when measuring resistance values online. Due to the small output current, the shunt of surrounding online capacitors, inductors, transistors, etc. is very small, so measuring the resistance value online is more accurate and convenient. Generally, it is not necessary to solder open the solder joints to measure whether the resistance value is normal.
For example, when measuring the PN junction of nonlinear devices, the current provided by a digital meter often differs significantly from the actual operating current, resulting in inaccurate judgment. At this point, the pointer table becomes very useful.
Two measuring tools, digital meters, can replace pointer meters more in the production measurement and control process. However, in fields such as technological development and maintenance, pointer meters still play an irreplaceable role.
