How to measure voltage drop

When the voltage of a power supply passes through a line or other components, part of the transmitted voltage will be consumed and reduced. This reduced part is the voltage drop of this line. The voltage at the starting point of the power supply and the voltage at the end point are measured, and the difference between the two is the voltage drop.

For example, if the output voltage of the substation is 220V and the voltage at your home is 215V, then the voltage drop from the substation to your home is 220V-215V=5V.

Measuring voltage drop with a multimeter is actually just like measuring AC or branch voltage. You just need to know the direction of the current in the circuit from which end it flows into the component, and then connect the red test lead to the end of the component where the current flows. The black pen is connected to the other end. Because: the voltage across the components in the circuit is called voltage drop, also called voltage drop. Its flow direction is the same as the current, so the end where the current flows into the component is the positive pole, and the end where the current comes out is the negative pole.

Note: When you want to measure, you need to know the voltage flowing into the component, whether it is DC or AC, and then after selecting the gear, the selected range must be larger than the actual range at the beginning to avoid burning the multimeter; finally, slowly lower the range to facilitate the final reading to be accurate! The specific method is as follows:

Method for detecting voltage drop using multimeter:

① Connect the multimeter's positive probe to the positive "top" of the wire being measured.

② Connect the negative probe of the multimeter to the negative end of the wire being measured (can be done in sections).

③ Ensure that the test leads are in good contact with the test points.

④ When measuring a component, ensure that the component is in working condition.

⑤Start the engine and record the multimeter reading.

⑥ If the multimeter reading is around 0V, it means that the measured component has no resistance and is in good condition.

⑦ When performing segmented measurement, if there is a voltage drop higher than 0.4V in a certain segment, it indicates that the component has high resistance and should be repaired or replaced.