The relationship between the angle of deflection of the pointer of a multimeter measuring resistance and resistance
Care should be taken when measuring resistance:
1. The measured resistance should be removed from the circuit and then measured.
2. The two pens should not be touched together for a long time.
3. Two hands can not touch the two pens at the same time the metal rod, or two pins of the measured resistance, it is best to use the right hand at the same time to hold the two pens
4. Long time not to use the ohm file, should be removed from the table battery.
Multimeter resistance measurement, reflected in the head of the measured actual current through the measured resistance, the greater the measured resistance, the smaller the current, that is, the smaller the deflection angle. The relationship between the pointer deflection angle and the measured resistance is:
α = (RZθ) / (RX + RZ)
Where: α - pointer deflection angle;
RZ --- multimeter centre resistance;
RX --- measured resistance;
θ --- pointer full deflection angle, the angle is more 90 °
From the multimeter ohm scale can be seen, the scale is uneven reverse scale, the smaller the deflection angle, the greater the indicated resistance value. In the high resistance end of each quarter line between the resistance value difference is very large, measurement, if in this section of the index line, the pointer to look at a deviation of an angle, will cause a large error. Especially when measuring small resistance, the error is more obvious. Therefore, in order to ensure the accuracy of the measurement, in the measurement of small resistance, should be shifted through the method, as far as possible to make the pointer in the centre of the position near.
