Method of distinguishing positive and negative poles of storage battery

 Judge according to the design characteristics of battery electrode 
During the production and design of commonly used storage batteries, the thicker end of the battery pile is a positive electrode, and the thinner end is a negative electrode. At the same time, you can identify the color of the battery pile. The positive electrode pile is dark brown, while the negative electrode is dark gray. In addition, the positive and negative marks of some batteries are expressed in English letters, that is, P represents positive electrode, and N represents negative electrode.

 Measure with multimeter voltage gear 
The multimeter can be switched to the DC gear, and the two probes are respectively connected to the two electrodes of the battery. At this time, if the battery displays a normal voltage value, it is proved that the electrode touched by the red probe is the positive electrode of the battery, while the black probe is the negative electrode. Sometimes it is measured that there is no normal voltage in the battery, then the weak micro storage capacity of the battery can be measured to judge. When the two probes touch the battery electrode, if the needle shakes slightly to the right, it proves that the red pen is the battery positive electrode and the black pen is the negative electrode. However, if the pointer of the multimeter shakes to the left (the pointer reverses), it proves that the place touched by the red pen is the negative electrode of the battery.

 Identification by wire short circuit 
Connect two copper core power lines to the electrodes of the old battery to be measured, pour the normally configured electrolyte (concentrated brine) into a glass teacup, insert both ends of the power line into the teacup, and place them on the edges of both sides of the glass cup respectively (the two lines cannot touch each other in the cup), and then observe the bubbling of each lead end in the electrolyte, If there are obvious and many bubbles on the end of a wire, it means that the end of the power line connecting the battery is the negative electrode, and the end with few but not obvious bubbles is the positive electrode of the battery.

 Measure with rectifier diode 
The rectifier diodes in the power supply regulator have unidirectional conductivity. You can find a rectifier diode. A 40w incandescent lamp. Then connect them in sequence according to one pile of the battery → diode+end → diode end → incandescent lamp → another pile of the battery to form a series circuit of electric lamps. At this time, if the incandescent lamp in the circuit is ignited and emits light, it proves that the connection between the diode end and the battery pile is the positive electrode of the battery, The other end is the negative electrode of the battery.

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