İşaretçi Multimetre Test İpuçları
Önce test işaretleyici multimetre, ilk, yer multimetre içinde bir yatay durum ve gör olsun onun iğne is at the zero point (the zero point of the akım ve voltaj ölçek), if not, ayarla the "mechanical zero adjustment" under the head to make the pointer point to the zero point. Doğru seç the measurement items and range switches on the multimeter. Eğer sırası büyüklük nın ile ölçülen değer bilinen, sonra seç tekin karşılık gelen aralık nın sırası nın büyüklüğü. Eğer sen yapmıyorum bilmiyorsun sırası büyüklük nın ölçülen değer, sen melisin seç maksimum aralık için başlangıç the ölçüm, ve sonra azalt aralık ne zaman açı of sapma nın çok küçük okumak doğru. genellikle, the saptırma açı of doğru. genellikle, the sapma açı of the pointer is değil az daha fazla 25 nın maksimum ölçek gibi bir makul aralık.
Voltmetre kullanım
Multimeter and connected to the circuit under test, in the measurement of DC voltage, should pay attention to the polarity of the measured voltage, that is, the red pen to the high voltage end, the black pen to the low voltage end. If you do not know the polarity of the measured voltage, you can try the test method as described above when measuring current, such as the pointer deflects to the right, you can measure; such as the pointer deflects to the left, the red and black pens are switched to a different location, can be measured. Measurement of the circuit's internal resistance is very large, it requires the voltmeter's internal resistance is larger, in order to make the measurement accuracy. At this time, you need to change the voltage sensitivity (greater internal resistance) of the multimeter to measure. In the measurement of AC voltage, do not have to consider the polarity of the problem, as long as the multimeter is connected in parallel to be measured at both ends can be. In addition, it is generally not necessary to choose a large range gear or select a high voltage sensitivity multimeter. The internal resistance of the AC power supply is smaller than the gel. It is worth noting that the measured AC voltage can only be sinusoidal, and its frequency should be less than or equal to the permissible operating frequency of the multimeter, otherwise it will produce a large error. Do not toggle the range selector switch when measuring higher voltages (e.g., 220v), so as not to produce an arc and burn the contacts of the changeover switch off. In the measurement of high voltage greater than or equal to 100v, must pay attention to good first - a pen fixed in the circuit under test in the public and then use another pen to touch the other - end of the test point. If the range is not enough, need to change another gear measurement in addition to the multimeter is only suitable for measuring the volume frequency level, such as DC voltage on the circuit, but also must be connected in series with a 0.1uF/450V capacitor will be the DC isolation and then measured, in the measurement of the inductive resistance of the circuit of the voltage must be measured after the measurement of the multimeter disconnected and then turn off the power. Otherwise, when cutting off the power supply, because of the self-inductive phenomenon of the inductive components in the circuit, it will produce high pressure and may burn out the multimeter.
Multimeter connected in series in the circuit under test, should pay attention to the direction of the current. That is to say, the red pen is connected to the end of the current inflow, and the black pen is connected to the end of the current outflow. If you do not know the direction of the measured current, you can connect a pen at one end of the circuit, another pen at the other end of the circuit gently touch, if the pointer swings to the right, indicating that the wiring is correct; if the pointer swings to the left (lower than zero), indicating that the wiring is incorrect, the multimeter should be switched to the position of the two pens. In the pointer deflection angle is greater than or equal to the maximum scale 20%, try to use a large range gear. Because the larger the range, the smaller the shunt resistance, the smaller the equivalent internal resistance of the ammeter, the smaller the error introduced by the measured circuit. In the measurement of large currents (such as 500mA), do not toggle the range selection switch during the measurement process, so as not to produce an arc, burn the contacts of the changeover switch.
