Pros and Cons of Conventional Analog Multimeters and Digital Multimeters
Digital multimeters are instantaneous sampling instruments. They sample once every 0.3 seconds to display measurement results. Sometimes the sampled results are only very close rather than completely identical, which makes reading results less convenient than with analog multimeters.
Analog multimeters generally have no built-in amplifiers and thus feature low internal resistance. For example, the Model MF-10 has a DC voltage sensitivity of 100 kΩ/V, which is among the best. The DC voltage sensitivity of Model MF-500 is 20 kΩ/V.
Digital multimeters employ operational amplifier circuits internally, so their internal resistance can be very high, often 1 MΩ or higher (which delivers higher sensitivity). This reduces impact on the circuit under test and provides high measurement accuracy.
Due to low internal resistance and shunt/voltage-divider circuits built from discrete components, analog multimeters have non-uniform frequency characteristics compared with digital types.
Analog multimeters have simple internal structures, leading to low cost, fewer functions, easy maintenance and strong resistance to overcurrent and overvoltage.
Digital multimeters integrate various oscillator, amplifier, frequency division and protection circuits, offering abundant functions such as temperature measurement, frequency measurement (within a low range), capacitance measurement, inductance measurement, and signal generation.
Since integrated circuits are widely used in their internal construction, digital multimeters have poor overload capability. (However, some modern models support auto-ranging and automatic protection, yet they are more complicated to operate.) They are generally difficult to repair once damaged.
Digital multimeters output low voltage (usually no more than 1 V), making it inconvenient to test components with special voltage characteristics, such as thyristors and light-emitting diodes.
Analog multimeters have a higher output voltage (10.5 V, 12 V, etc.) and larger output current (for instance, approximately 100 mA on the R×1Ω range of MF-500). They can conveniently test thyristors, light-emitting diodes and other components.
