Universal charger is also divided into positive and negative terminals, at present, many universal chargers have automatic detection function inside, when the battery is detected to automatically adjust the circuit to change the positive and negative terminals to meet the power supply needs. There is also a need to manually flip the switch to convert the positive and negative poles. Because the universal charge in your hand automatically detects the positive and negative electrodes of the mobile phone battery, whether you put positive or negative, it will identify the positive and negative electrodes and automatically convert to achieve charging.
Everything is different. Some have only one light, some have two lights. I used a lamp. There are no positive and negative poles, and if the battery has a tendency to explode, it can only be said that the battery has a problem. It has nothing to do with everything. It's a different story if you buy a cheap universal charger. The two lights are divided into positive and negative poles, a red and a green, the red is bright, and the green is flashing.
Points of positive and negative electrodes, the early universal charge must adjust the positive and negative electrodes can be charged, and later developed to a switch toggle can be exchanged, and now the universal charge automatically identifies the positive and negative electrodes when plugging in the battery, there are still positive and negative points, but the recognition process is automated