The knob is selected to a larger range than the estimated value, and the pen is connected to both ends of the power supply or battery to maintain stable contact. The value can be read directly from the display screen, if it is displayed as \"1.\
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If \"-\" appears on the left side of the value, it indicates that the pen polarity is opposite to the actual power supply polarity, and the red pen is connected to the negative pole.
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First of all, we need to prepare a multimeter, and then set the multimeter to zero, so that the error can be minimized, and then set the multimeter to DC voltage to indicate that the measurement is DC voltage. Some voltmeters may want to choose a range, the voltage of the graphics card is generally around 1V, so choose a smaller range.