Usage Instructions and Precautions for Digital Multimeters
Nowadays, digital measuring instruments have become mainstream and there is a trend to replace analog instruments. Compared with analog instruments, digital instruments have high sensitivity, accuracy, clear display, strong overload capacity, are easy to carry, and are simpler to use. Briefly introduce its usage and precautions.
Digital multimeters have the advantages of easy measurement, convenient value taking, and complete functions, making them popular among radio enthusiasts. Ordinary digital square meters generally include resistance measurement, on-off sound detection, and diode forward conduction voltage measurement. AC/DC voltage and current measurement, transistor amplification factor and performance measurement, etc. Some digital multimeters have added functions such as capacitance measurement, frequency measurement, temperature measurement, data memory, and voice reporting, which bring great convenience to practical testing work. However, improper use can easily cause damage to the components inside the meter during actual testing, resulting in malfunctions. Based on the actual situation causing damage to the digital multimeter, summarize the precautions that should be taken during the use of the digital multimeter for beginners to refer to, in order to prevent damage to the digital multimeter as much as possible.
Most cases of damage to a digital multimeter are caused by measurement gear errors. For example, when measuring AC power, if the measurement gear is set to the resistance gear, once the probe contacts the power, it can instantly cause damage to the internal components of the multimeter. Therefore, before using a multimeter for measurement, it is necessary to check whether the measurement gear is correct. After use, place the measurement selection at AC 750V or DC 1000V, so that no matter what parameter is mistakenly measured in the next measurement, it will not cause damage to the digital multimeter
Some digital multimeters are damaged due to the measured voltage and current exceeding the range. For example, measuring the mains power in the AC 20V range can easily cause damage to the AC amplifier circuit of the digital multimeter, causing the multimeter to lose its AC measurement function. When measuring DC voltage, if the measured voltage exceeds the measurement range, it can also easily cause circuit faults in the meter. When measuring current, if the actual current value exceeds the range, it usually only causes the fuse in the multimeter to burn out and will not cause any other damage. So when measuring voltage parameters, if you don't know the approximate range of the measured voltage, you should first set the measurement mode to measure its value, and then shift gears to obtain a comparative value of
If the voltage value to be measured far exceeds the maximum range that the multimeter can measure, a high resistance measuring probe should be provided separately. To detect the anode high voltage and focusing high voltage of black and white color TVs.
