How does a multimeter measure current
The multimeter can not only be used to measure the resistance of the object to be measured, but also the AC and DC voltage can also be used to measure the DC voltage.
How to measure current with a multimeter:
1. Select the range: The DC current range of the multimeter is marked with "mA" and has three ranges of 1mA, 10mA and 100mA. The selection of the range should be based on the current in the circuit.
2. Measurement method: The multimeter should be connected in series with the circuit under test. After the corresponding part of the circuit should be disconnected, connect the multimeter test leads to both ends of the breakpoint. The red test lead should be connected to the breakpoint connected to the positive pole of the power supply, and the black test lead should be connected to the breakpoint connected to the negative pole of the power supply.
Connect the circuit to make the LED light up normally.
Before use, it is required to prepare the multimeter and set the selector switch to the mA range of 100mA.
Disconnect the lead between the middle point of the potentiometer and the negative terminal of the light-emitting diode to form a "breakpoint".
Connect a multimeter in series at the breakpoint. The red test lead is connected to the negative electrode of the light-emitting diode, and the black test lead is connected to the middle point lead of the potentiometer.
Correctly read the current value through the LED. Record: The current through the LED is xx mA.
Rotate the potentiometer handle to observe the change of the pointer of the multimeter and the change of the brightness of the light-emitting diode.
Through the above operations, you can further understand the role of resistors in circuits.
After the measurement is completed, disconnect the power supply and store the multimeter as required.
