How to read when the digital multimeter measures DC current
In the 20MA gear, it shows 0.16 is 0.16mA.
In the 200MA block, it shows 1.6 is 1.6mA.
In the 20A block, it shows that 0.16 is 160mA (that is, 0.16A).
Instructions
Digital multimeters are relatively simple measuring instruments. In this article, the author will teach you how to use the digital multimeter correctly. Starting from the digital multimeter's voltage, resistance, current, diode, triode, MOS field effect tube measurement and other measurement methods, let you better grasp the multimeter measurement method.
Before use, you should carefully read the relevant instruction manual, and be familiar with the functions of the power switch, range switch, jack, and special jack.
1. Put the ON/OFF switch in the ON position, check the 9V battery, if the battery voltage is insufficient, it will be displayed on the display, and the battery needs to be replaced at this time. If the display does not show, follow the steps below.
2. The symbol next to the test pen socket indicates that the input voltage or current should not exceed the indicated value, which is to protect the internal circuit from damage.
3. Before the test. The function switch should be set to the range you need.
Precautions
To avoid electric shock and personal injury, please read the "Safety Information" and "Warnings and Cautions" in the manual before use. The following specifications are general and general specifications:
1. Do not use the instrument if it is damaged. Before using the meter, inspect the case and especially the insulation around the terminals.
2. Check the test leads for damaged insulation or exposed metal; check the continuity of the test leads; replace damaged test leads before use.
3. Do not use the instrument after abnormal use, its protection circuit may fail, if in doubt, please send the instrument for repair.
4. Do not use the instrument in explosive gas, water vapor or dusty environment.
5. Do not input the rated voltage marked on the meter on the meter terminals (two input ports, or any input port and earth).
6. Before use, use a meter to measure a known voltage to confirm that the meter is normal.
7. When measuring current, please turn off the power of the circuit before connecting the meter to the circuit.
8. When maintaining the instrument, please only use the parts marked or provided by the manufacturer.
9. The instrument must be used according to the method specified in this manual, otherwise the protective measures provided by the instrument may be invalid.
10. When measuring AC voltage with an effective value of 30V, an AC voltage with a peak value of 42V, or a DC voltage above 60V, please pay special attention, because such voltages may cause electric shock.
How to measure current with multimeter
The method is shown in the figure below:
(1) Connect the circuit to make the light-emitting diode glow normally.
(2) Prepare the multimeter according to the pre-use requirements mentioned above and set the selection switch to the mA range of 100mA.
(3) Disconnect the lead wire between the junction point of the potentiometer and the negative electrode of the light-emitting diode to form a "breakpoint". At this time, the LED goes out.
(4) Connect the multimeter in series at the breakpoint. The red test lead is connected to the negative pole of the light-emitting diode, and the black test lead is connected to the middle contact lead of the potentiometer. At this time, the light-emitting diodes light up again. The scale value pointed by the pointer of the multimeter is the current value passing through the LED.
(5) Correctly read the current value through the light-emitting diode.
(6) Rotate the handle of the potentiometer to observe the changes of the pointer of the multimeter and the brightness of the light-emitting diodes.
(7) After the measurement is completed, disconnect the power supply and put away the multimeter as required.
