Selection of Analog Multimeters and Digital Multimeters
1. The reading accuracy of pointer meters is poor, but the process of pointer oscillation is relatively intuitive, and the amplitude of its oscillation speed can sometimes objectively reflect the size of the measured object (such as the slight jitter of the TV data bus (SDL) when transmitting data); The reading of a digital multimeter is intuitive, but the process of digital changes looks messy and difficult to observe.
2. There are usually two batteries inside a pointer meter, one with a low voltage of 1.5V and the other with a high voltage of 9V or 15V. The black probe is the positive terminal relative to the red probe. A digital multimeter typically uses a 6V or 9V battery. In the resistance mode, the output current of the pointer meter is much larger than that of the digital meter, using R&TImes; 1 Ω mode can make the speaker emit a loud "click" sound, using R&TImes; The 10k Ω range can even light up the light-emitting diode (LED).
3. In the voltage range, the internal resistance of the pointer meter is relatively small compared to the digital multimeter, and the accuracy of the measuring instrument is relatively poor. In some high-voltage microcurrent situations, it is even impossible to measure accurately because its internal resistance can affect the tested circuit (for example, when measuring the acceleration voltage of a TV cathode ray tube, the measured value may be much lower than the actual value). The internal resistance of the voltage range of a digital multimeter is very high, at least in the megaohm range, and has little impact on the tested circuit. However, 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 short, pointer meters are suitable for measuring analog circuits with relatively high current and high voltage, such as televisions and audio amplifiers. Digital meters are suitable for measuring low voltage and low current digital circuits, such as BP machines, mobile phones, etc. Not absolute, you can choose a pointer meter and a digital multimeter according to the situation.
