Multimeter usage formula
1. When measuring, look at the block first, if you don't look at it, don't measure
Every time you pick up the test leads to prepare for measurement, be sure to check again whether the measurement type and range selection switch are in the correct position. To be safe, this habit must be developed.
2. Do not shift the gear when measuring, after the measurement, shift the neutral gear
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.
3. The dial should be level and the reading should be aligned
When using the multimeter, it should be rotated horizontally, and the sight should be facing the needle when reading.
4. The range should be appropriate, and the needle should be more than halfway off.
When selecting 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 size of the deflection angle, until the pointer is deflected to about 2/3 of the full scale.
5. The R is not charged, and the C is discharged first
It is strictly forbidden to measure resistance when the circuit under test has a point. When checking large-capacity capacitors on electrical equipment, the capacitors should be short-circuited and discharged before measurement.
6. Set zero first when measuring R, and need to set 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.
7. The black 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 on the electric block is connected to the positive electrode of the internal battery.
8. 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.
9. The polarity is not reversed, and one hand becomes a habit
When measuring current and voltage, special attention should be paid to the polarity of the red and black test leads that cannot be reversed, and the habit of one-handed operation must be developed to ensure safety.
