Loudspeaker

Nowadays as the classroom becoming bigger and bigger, the voice of the teacher has been required a lot. However some teachers have a low voice when they were born. It is difficult for them to extend their voice in every corner of the classroom. In order to solve the problem, some schools or the teachers themselves choose the loudspeaker.

It can somehow solve the problem. However when you use it, you may also find a problem that when we use it, it may be out of energy. In fact, the battery of loudspeaker can be used at least 1 week. However when we use it, we may ignore the charge. Once when I had a class with students, the battery was out of energy fully. Then I had to continue the class without it which made me so tired.

Actually there is a sign when the energy of the battery is nearly used up. When you find that even though you use the loudspeaker, you should speak louder than before, you can make a full charge of the battery.