The principle of selecting multimeter

- Mar 22, 2018-

1, the pointer table reading accuracy is poor, but the process of the pointer swinging more intuitive, the amplitude of the swing can sometimes reflect the measured size objectively (for example, the slight jitter of the television data Bus (SDL) in the transmission); The digital table readings are intuitive, but the process of changing numbers looks messy and is not easy to watch.

2, the indicator table generally has two batteries, a low voltage 1.5V, a high voltage of 9V or 15V, its black pen relative to the red pen is the positive end. A 6V or 9V battery is commonly used for digital tables. In the resistor file, the pointer table pen output current relative to the digital table is much larger, with rx1ω file can make the speaker loud "clatter" sound, with rx10kω file can even light light-emitting diode (LED).

3, in the voltage file, the indicator table resistance relative to the digital table is relatively small, measuring accuracy compared to poor. Some high voltage micro-currents can not even be measured, because their internal resistance will affect the circuit under test (for example, in the measurement of the television tube of the acceleration level of the measured value will be much lower than the actual value). The internal resistance of the digital meter voltage file is very large, at least in the gigabit Europe, it has little influence on the circuit being measured. But the extremely high output impedance makes it susceptible to the influence of the inductive voltage, in some cases of strong electromagnetic interference measured data may be virtual.

4, in short, in the relatively large current high-voltage analog circuit measurement application of the pointer table, such as television, audio amplifier. In low voltage and small current digital circuit measurement application of digital meters, such as BP machine, mobile phones and so on. Not absolute, can choose the pointer table and the numerical table according to the situation.