Choice of digital multimeter and analog multimeter
1. The reading accuracy of the pointer meter is poor, but the process of the pointer swinging is relatively intuitive, and its swing speed can sometimes reflect the measured size more objectively (such as measuring the slightness of the TV data bus (SDL) when transmitting data). Jitter); the digital meter reading is intuitive, but the process of digital changes looks messy and not easy to watch.
2. There are generally two batteries in an analog watch, one with a low voltage of 1.5V and one with a high voltage of 9V or 15V. The black test lead is the positive terminal relative to the red test lead. Digital meters commonly 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. Using the R×1Ω gear can make the speaker make a loud "click" sound, and using the R×10kΩ gear can even light up the light-emitting diode (LED).
3. In the voltage range, the internal resistance of the pointer meter is smaller than that of the digital meter, and the measurement accuracy is relatively poor. In some high-voltage and micro-current situations, it is even impossible to measure accurately because the 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 impact 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 situations with strong electromagnetic interference.
4. In short, pointer meters are suitable for measuring analog circuits with relatively large currents and high voltages, such as televisions and audio amplifiers. Digital meters are suitable for measuring digital circuits with low voltage and small current, such as BP machines, mobile phones, etc. It is not fixed, and a pointer table and a digital table can be selected according to the situation.
