Comparison of resistance files between digital multimeter and pointer multimeter
The digital type has a gear for measuring diodes, but the pointer type does not. For unstable parameters, the digital type is not as good as the pointer type, but the digital type has higher precision and clear display, unlike the pointer type, which requires different scales to be selected according to different gears.
working principle:
The pointer table is used by using electromagnetic induction and simple electronic circuit, and the digital table is applied by digital circuit processing and digital display! Pointer resistance measurement is convenient, economical, durable, afraid of falling, and inconvenient to read; digital meter is intuitive, high cost, and general protection function!
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. Meter head: It is a high-sensitivity magnetoelectric DC ammeter. The main performance indicators of the multimeter basically depend on the performance of the meter head. The sensitivity of the meter head refers to the DC current value flowing through the meter head when the pointer of the meter head is deflected at full scale. The smaller the value, the higher the sensitivity of the meter head. The greater the internal resistance when measuring voltage, the better its performance. There are four scale lines on the meter head, and their functions are as follows: the first line (from top to bottom) is marked with R or Ω, which indicates the resistance value. When the switch is in the ohm block, read this scale line. The second bar is marked with ∽ and VA, indicating the AC, DC voltage and DC current value. When the transfer switch is in the AC, DC voltage or DC current gear, and the range is at a position other than AC 10V, read this scale Wire. The third line is marked with 10V, which indicates the AC voltage value of 10V. When the switch is in the AC and DC voltage range and the range is at AC 10V, read this scale line. The fourth bar, labeled dB, indicates the audio level.
5. The digital meter must be powered on to run (usually with a 9V laminated battery). The pointer meter does not need battery power when measuring voltage and current. 6. The digital meter reads directly, and the reading of the pointer meter is relatively not as direct as that of the digital meter. 7. In terms of dynamic measurement of voltage and current, digital meters (digital meters without oscilloscope function) are not as intuitive as pointer meters. 8. In terms of earthquake resistance and drop resistance, pointer watches are far inferior to digital watches. 9. The function of the digital meter can be extended to measure frequency, capacitance, logic channel, triode magnification, etc. The pointer meter usually only has three levels of resistance, voltage and current. Hope the above answers can help you understand the differences between digital watches and pointer watches.
The pointer multimeter directly drives the needle after the analog current and voltage are rectified, shunted, and divided, and the corresponding indication is made on the dial. When measuring passive components (such as resistance, capacitance, transistor, etc.), the battery in the meter is used as the power source, and the red test lead is connected to the negative pole of the battery. The digital multimeter is not only called a digital meter because it displays numbers, it converts the collected analog signals into digital signals through "digital-to-analog conversion", re-encodes, and displays the measured values by the display drive circuit and display components. At the same time There are also integrated operational circuits such as sampling, comparison, and amplification. When in use, there must be a battery in the meter to provide power for the circuit in the meter. Unlike the pointer multimeter (also called an analog multimeter), the red pen is a high potential. The selection of gears during measurement is similar to the voltage and current gears of the pointer multimeter, and the reading of the pointer multimeter when measuring resistance is the multiplier of the indicated value multiplied by the selected range gear. Generally, the error of digital meter is smaller than that of pointer multimeter.
