The difference between pointer multimeter and digital multimeter in use
1. The reading accuracy of the pointer meter is poor, but the process of the pointer swing is more intuitive, and its swing speed range can sometimes objectively reflect the size of the measured value (such as the slight deviation of the TV data bus (SDL) when transmitting data. jitter); the reading of the digital meter is intuitive, but the process of digital change looks messy and not easy to watch.
2. There are generally two batteries in the pointer meter, one is low voltage 1.5V, the other is high voltage 9V or 15V, and the black test lead is positive terminal relative to the red test lead. Digital meters usually use a 6V or 9V battery. In the resistance mode, the output current of the test pen of the pointer meter is much larger than that of the digital meter. The loudspeaker can make a loud "da" sound with the R×1Ω gear, and the light-emitting diode (LED) can even be lit with the R×10kΩ gear.
3. In the voltage range, the internal resistance of the pointer meter is relatively small compared with the digital meter, and the measurement accuracy is relatively poor. Some occasions with high voltage and micro current cannot even be measured accurately, because its internal resistance will affect the circuit under test (for example, when measuring the acceleration stage voltage of a TV picture 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 large, at least in the megohm level, and has little effect on the circuit under test. However, the extremely high output impedance makes it susceptible to the influence of induced voltage, and the measured data may be false in some occasions with strong electromagnetic interference.
4. In short, pointer meters are suitable for the measurement of analog circuits with relatively high current and high voltage, such as TV sets and audio amplifiers. It is suitable for digital meters in the measurement of low-voltage and low-current digital circuits, such as BP machines, mobile phones, etc. It is not fixed, and pointer tables and digital tables can be selected according to the situation.
