When the square dance stereo used to still have a grid of electricity when you have to charge in time, fully charged, you then auxiliary charging one to two hours, to ensure that the battery is full on the line. It can be seen that the square dance stereo is fully charged with four cells with three cells and then recharge.
Audio specifically refers to the combination of electrical equipment to emit sound of a set of audio systems. The history of the development of audio technology can be divided into four stages: electronic tubes, transistors, integrated circuits, field effect tubes.