The selection method of pointer type multimeter and digital multimeter
1. The reading accuracy of the pointer meter is poor, but the process of pointer oscillation is more intuitive, and the amplitude of its oscillation speed can sometimes objectively reflect the measured size (such as the slight jitter of the TV data bus (SDL) when transmitting data); The reading on the digital meter is intuitive, but the process of number changes looks messy and not easy to observe.
2. A pointer usually has two batteries inside, one with a low voltage of 1.5V and the other with a high voltage of 9V or 15V. The black probe is relatively positive compared to the red probe. A digital meter often uses a 6V or 9V battery. In the resistance range, the output current of the pointer meter is much larger than that of the digital meter. Using the R × 1 Ω range can make the speaker emit a loud "click" sound, and using the R × 10k Ω range can even light up the light-emitting diode (LED).
3. In the voltage range, the internal resistance of a pointer meter is relatively small compared to a digital meter, and the measurement accuracy is relatively poor. In some high voltage and low current situations, it is even impossible to accurately measure because its internal resistance can affect the tested circuit (for example, when measuring the acceleration stage voltage of a television tube, the measured value will be much lower than the actual value). The internal resistance of the voltage range of the digital meter is very high, at least in the megaohm level, and has little impact on the tested circuit. But the extremely high output impedance makes it susceptible to the influence of induced voltage, and the data measured in some situations with strong electromagnetic interference may be false.
4. In summary, pointer meters are suitable for analog circuit measurements with relatively high current and voltage, such as television and audio amplifiers. Digital meters, such as mobile phones, are suitable for measuring low voltage and low current digital circuits. Not absolute, pointer and digital meters can be selected according to the situation.
