Introduction to the Comparison between Pointer Multimeter and Digital Multimeter
A pointer multimeter is an average-value type instrument, which has an intuitive and vivid reading indication. (Generally, the reading value is closely related to the swinging angle of the pointer, so it is very intuitive). A digital multimeter is an instantaneous sampling type instrument. It samples once every 0.3 seconds to display the measurement result. Sometimes, the results of each sampling are only very similar, not exactly the same, which makes it less convenient to read the results compared with the pointer type.
A pointer multimeter generally does not have an amplifier inside, so its internal resistance is relatively small. For example, for the MF-10 model, the DC voltage sensitivity is 100 kΩ/V. The DC voltage sensitivity of the MF-500 model is 20 kΩ/V. Since the digital multimeter uses an operational amplifier circuit inside, its internal resistance can be made very large, often 1 MΩ or more. (That is, it can achieve higher sensitivity). This enables it to have less impact on the measured circuit and achieve higher measurement accuracy.
Due to its relatively small internal resistance, the pointer multimeter mostly uses discrete components to form the shunt and voltage division circuits. Therefore, its frequency characteristics are uneven (compared with the digital multimeter), while the pointer multimeter has relatively better frequency characteristics in this regard. The internal structure of the pointer multimeter is simple, so the cost is low, the functions are few, the maintenance is easy, and its ability to withstand overcurrent and overvoltage is relatively strong. The digital multimeter uses a variety of oscillation, amplification, frequency division protection and other circuits inside, so it has more functions. For example, it can measure temperature, frequency (within a relatively low range), capacitance, inductance, and be used as a signal generator, etc.
Since the internal structure of the digital multimeter mostly uses integrated circuits, its overload capacity is relatively poor. (However, some can now automatically shift gears and have automatic protection functions, etc., but they are more complicated to use), and it is generally not easy to repair after being damaged. The output voltage of the digital multimeter is relatively low (usually not exceeding 1 volt), which is inconvenient for testing some components with special voltage characteristics (such as thyristors, light-emitting diodes, etc.). The pointer multimeter has a higher output voltage (such as 10.5 volts, 12 volts, etc.) and a larger current (for example, the MF-500 *1Ω gear can have a maximum current of about 100 mA), which can conveniently test thyristors, light-emitting diodes, etc.
