The principle of multimeter measuring resistance
The principle of measuring resistance with a multimeter is actually based on Ohm's law. In the multimeter, its voltage is the voltage of the battery; it has several resistance values, including the resistance we want to test, its adjustable resistance (the internal resistance of the multimeter is different for different gears), and its fixed resistance. And the current is calculated when our test resistance is equal to zero. In this way, we can get a formula: |=U/(Rg+Rset+Radjustment+Rmeasurement), U is the voltage of its internal battery, Rg is the resistance of the meter head, R is fixed, and the meter is connected in series A fixed value resistor, Radjustment, a variable resistor for zero adjustment, Rmeasurement, the resistance to be measured. Depending on the range of resistance to be measured, the fixed-value resistance used is also different, which makes the multimeter divided into several levels.
When measuring with a multimeter, the resistance reading is actually the current reading, just mark the current when R=0: |=U/ (Rg+Rset+Rtune) as R=0, and when there is no current, the resistance is marked at no resistance , I and is a functional relationship, they are not a simple proportional relationship. Different resistance files are selected, and R is set differently. When R=0, it is different, so it must be zeroed before each measurement.
