Distinctions Between Pointer Multimeters and Digital Multimeters
The analog multimeter is an average-value instrument with intuitive and visual reading indication. (The reading value is closely related to the deflection angle of the pointer, so readings are very straightforward.) The digital multimeter is an instantaneous sampling instrument. It samples once every 0.3 seconds to display measurement results. Sometimes successive sampling results are only very close rather than completely identical, making reading less convenient than with analog multimeters.
Analog multimeters generally contain no internal amplifiers and thus have low internal resistance, with DC voltage sensitivity of 100 kΩ/V or 20 kΩ/V. Digital multimeters adopt operational amplifier circuits internally, so their internal resistance can be very high, often 1 MΩ or higher (which delivers higher sensitivity). This minimizes interference to the circuit under test and achieves high measurement accuracy.
Since analog multimeters have low internal resistance and mostly use discrete components to build shunt and voltage divider circuits, their frequency characteristics are non-uniform compared with digital multimeters.
Analog multimeters feature simple internal structures, resulting in low cost, fewer functions, easy maintenance and strong resistance to overcurrent and overvoltage. Digital multimeters integrate various oscillator, amplifier, frequency division and protection circuits, providing abundant functions such as temperature measurement, frequency measurement (within a low range), capacitance measurement, inductance measurement, and signal generation.
Digital multimeters rely heavily on integrated circuits internally and therefore have poor overload capability. (However, some modern models support auto-ranging and automatic protection, though their operation is relatively complex.) They are generally difficult to repair once damaged.
Digital multimeters output low voltage (usually no more than 1 V), which brings inconvenience for testing components with special voltage characteristics such as thyristors and light-emitting diodes. Analog multimeters provide higher output voltage (10.5 V, 12 V, etc.) and larger output current (approximately 100 mA on the R×1Ω range of the MF-500 model). They can conveniently test thyristors, light-emitting diodes and other components.
Beginners are recommended to use analog multimeters, while experienced users can employ both types of instruments.
