14 Unique Tips for Using Your Multimeter
We all know that the multimeter is an indispensable common maintenance tool in the work of electrical workers. Correct use of the multimeter can not only make our work more efficient, but also improve the safety and efficiency of our work.
1. Before using the multimeter, "mechanical zero adjustment" should be performed first;
2. Do not touch the metal part of the test pen with your hands during the measurement process, which not only ensures the accuracy of the measurement, but also ensures personal safety;
3. In a complex environment, it is necessary to pay attention to the influence of the external magnetic field on the multimeter;
4. In order to improve the measurement accuracy, try to keep the pointer of the multimeter in the middle position when measuring. The measuring range should be appropriate, and the needle should be offset by more than half. Select the range, if it is impossible to estimate the measured size in advance, you should try to choose a larger range, and then gradually change to a smaller range according to the deflection angle, until the pointer is deflected to about 2/3 of the full scale;
5. When using a multimeter to test components with positive and negative polarity such as transistors and electrolytic capacitors, pay attention to the polarity relationship. The black and negative should be remembered clearly, and the black in the table should be connected to "+". The red test lead is the positive electrode, and the black test lead is the negative electrode, but the black test lead is connected to the positive electrode of the internal battery.
6. If the multimeter needs to be shifted, the test leads should be disconnected first, and then the measurement should be performed after shifting. Do not switch gears when measuring, and switch neutral gears after measuring. During the measurement, the selection knob cannot be turned arbitrarily, especially when measuring high voltage (such as 220V) or high current (such as 0.5A), so as to avoid arcing and burning out the contacts of the transfer switch. After the measurement is completed, the range selection switch should be turned to the "•" position;
7. When measuring resistance, zero adjustment should be performed every time the gear is changed. If it is not adjusted to zero, replace the battery with a new one. When measuring R, adjust zero first, and then adjust to zero when shifting gears. When measuring resistance, first turn the switch to the electric block, short-circuit the two test leads, and turn the "Ω" zero-adjustment potentiometer to make the pointer point to zero ohms before measuring. The ohmic zero should be readjusted every time the electrical barrier is replaced;
8. After the multimeter is used, the transfer switch should be placed in the maximum block of AC voltage;
9. If it is not used for a long time, the internal battery of the multimeter should be taken out to prevent the battery from corroding other devices in the meter;
10. When measuring, look at the block first, and do not measure without looking. Every time you pick up the test leads and prepare to measure, be sure to check again whether the measurement category and range selection switches are in the correct positions. To be safe, this habit must be cultivated;
11. The dial should be level and the readings should be aligned. When using the multimeter, it should be rotated horizontally, and the sight should be facing the needle when reading;
12. The test R is not charged, and the test C is discharged first. It is strictly forbidden to measure resistance when the circuit under test has a point. When checking the large-capacity capacitors on electrical equipment, the capacitors should be short-circuited and discharged before measurement;
13. The measurement I should be connected in series, and the measurement U should be connected in parallel. When measuring current, the multimeter should be connected in series in the circuit under test; when measuring voltage, the multimeter should be connected in parallel at both ends of the circuit under test;
14. The polarity is not reversed, and one hand becomes a habit. When measuring current and voltage, special attention should be paid to the polarities of the red and black test leads that cannot be reversed, and the habit of one-handed operation must be developed to ensure safety.
