Precautions when using a handheld digital multimeter
Handheld digital multimeter It has accurate measurement, easy to take values, full-featured and other advantages, so by our radio enthusiasts welcome, ordinary handheld digital multimeter generally has a resistance measurement, it passes off the sound detection, diode conduction voltage measurement. AC and DC voltage and current measurement, triode amplification and performance measurement. There are individual digital multimeter is increased capacitance measurement, frequency measurement, temperature measurement, data memory and voice reporting and other functions, to bring great convenience to the actual test work. However, the portable digital multimeter due to improper use, in the actual detection of easy to cause damage to the table components, resulting in failure. Jintai science and technology according to cause damage to the digital multimeter of the actual situation, summed up the digital multimeter in the use of the precautions, only for the reference of the beginner, in order to try to prevent the damage of the handheld digital multimeter.
Digital multimeter damage in most cases is caused by the measurement of the wrong gear, such as in the measurement of the AC mains, the measurement of the gear selection is placed in the resistance block, in this case, once the pen contact with the mains, instantly can cause damage to the internal components of the multimeter. Therefore, you must check whether the measuring position is correct before using the multimeter. At the end of the use, the measurement selection will be placed in the AC 750V or DC 1000V, so that in the next measurement, no matter what parameters are measured by mistake, will not cause damage to the digital multimeter.
Handheld digital multimeter when using the precautions two. Individual digital multimeter damage is due to the measurement of voltage and current over the range caused by the range. Such as in the AC 20V gear measurement of utility power, it is easy to cause damage to the digital multimeter AC amplifier circuit, so that the multimeter to lose the AC measurement function. In the measurement of DC voltage, the measured voltage exceeds the measurement range, also easy to cause the table circuit failure. When measuring current, if the actual current value exceeds the range, it will only cause the fuse in the multimeter to blow, and will not cause other damages. Therefore, when measuring voltage parameters, if you don't know the approximate range of the measured voltage, you should first put the measurement gear at 0, and then change the gear after measuring its value to get a more accurate value. If the voltage value to be measured is far beyond the maximum range that the multimeter can measure, it should be equipped with another high resistance measuring pen. Such as detecting the anode high voltage and focusing high voltage of black and white colour TV.
The upper range of DC voltage of most digital multimeters is 1000V, so when measuring DC voltage, the maximum voltage value is below 1000V, which generally will not damage the multimeter. If it exceeds 1000V, it is likely to cause damage to the multimeter. However, the upper limit of measurable voltage may vary from one digital multimeter to another. If the measured voltage exceeds the range, it can be measured by resistor step-down method. In addition, in the measurement of 40O ~ 1000V DC high voltage, the pen and the measurement must be in good contact, there can not be any jitter, otherwise, in addition to may cause damage to the multimeter and make the measurement inaccurate, serious cases can also make the multimeter without any display.
In addition, the electrician in the measurement of resistance, should pay attention to must not be charged to measure the digital multimeter.
