Method for measuring DC current of a multimeter
1. Insert the black lead into the COM jack. When measuring a maximum current of 200mA, insert the red lead into the mA jack. When measuring a maximum current of 20A, insert the red lead into the 20A jack.
2. Place the function switch in the DC current range A - appropriate range.
3. Connect the test probe in series to the load to be tested, maintain stability, and then read. If it shows "1.", then the range needs to be increased. If "-" appears to the left of the value, it indicates that the current flows from the black probe into the multimeter.
Operation tips
1. Select the DC current gear, and when the current range is unknown, start from the maximum range.
2. Pay attention to the direction of the current, that is, the red lead is connected to the positive pole (or high potential), and the black lead is connected to the negative pole (or low potential) of the power supply.
3. The meter should be connected in series in the circuit of the measured current.
4. The method of measuring AC current is similar to that of measuring DC current, but there is no polarity limitation.
Measurement steps for DC current
Step 1: Rotate the multimeter to the 200mA DC current range.
Step 2: Close S1 on the physical circuit.
Step 3: Connect the red lead to 1 and the black lead to 2, observe the reading, and measure that the current between points 1 and 2 in the branch is 20mA.
4、 Precautions
1. If the measured current range is not known before use, set the function switch to the maximum range and gradually decrease.
2. If the display is "1.", it indicates that the range is too small and the function switch should be set to a higher range.
3. The maximum input current is 200mA. Excessive current will burn out the fuse and it should be replaced. The 20A range has no fuse protection and cannot exceed 15 seconds during measurement.
4. The measurement method of AC current is the same as that of DC, but the gear should be set to AC gear A~. After the current measurement, the red pen should be inserted back into the "V Ω" hole. If you forget this step and directly measure the voltage, the meter or power supply will be scrapped. Please operate carefully!
How to use a digital multimeter to measure DC current_ Digital multimeter
Instructions for measuring current using a multimeter
Ideally, the internal resistance of the current range should be equal to zero, but in reality it cannot be achieved. Due to the presence of internal resistance, there will inevitably be a certain voltage drop when using a multimeter to measure current, resulting in measurement errors.
The smaller the internal resistance of the current range, the lower the electrical power consumed by the multimeter when measuring current.
1. When the current range is the same, the smaller the internal resistance of the multimeter, the lower the full scale voltage drop, and the smaller the error in measuring current. For the same multimeter, the full scale voltage drop values for each current range can be different.
2. For the same multimeter, the larger the current range, the smaller the internal resistance, and the smaller the measurement error. Therefore, in order to reduce the error in measuring current, it is sometimes preferable to choose a higher current range. Of course, the range should not be too high to avoid a significant increase in reading error when measuring small currents.
3. When the internal resistance of the current range is about 1% of the total resistance of the circuit being tested, there is no need to consider the multimeter voltage
