How to connect the red and black test leads: 1. For the voltage and current settings of the voltmeter, ammeter or multimeter, the red test lead is connected to the positive pole, and the black test lead is connected to the negative pole; 2. For the electrical barrier of the multimeter, that is the black The test lead is equivalent to the positive terminal of the battery, and the red test lead is equivalent to the negative terminal of the battery.
The operating environment of this tutorial: Windows 7 system, Dell G3 computer.
If it is the voltage and current range of a voltmeter, ammeter or multimeter, the red test lead is connected to the positive pole, and the black test lead is connected to the negative pole; red in and black out means that all currents have the red test lead entering from the black test lead outflow.
If it is the electrical barrier of the multimeter, then the black test lead is equivalent to the positive electrode of the battery, and the red test lead is equivalent to the negative electrode of the battery; because when measuring resistance (there is no external power supply) , then the current through the resistor is provided by the ohmmeter itself. At this time, for the ohmmeter, the black pen is connected to the positive pole of the internal power supply, and the red pen is connected to the negative pole
Inside the multimeter, the red pen is actually connected to the internal The negative terminal of the battery and the black test lead are actually connected to the positive terminal of the internal battery. Regardless of measuring resistance (using the internal battery) or current or voltage (using an external power supply), the direction of the current is always flowing in from the red test lead and flowing out from the test lead.
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