The TV and laptop computer in our classroom, each lecture is at the beginning of the good, the effect is very good, but use started to make noise, can not be used, in other locations, like the school office, it is very easy to use without a murmur, who can give me explain. Or tell me how to repair. + I QQ397166324 useful words, must give points
Judging from what you say, now divided into several cases. One is the internal resistance of the power supply has increased, two is a bad contact plug at the audio input, three is the external electromagnetic interference. You had good, that power is no problem. It is recommended to check the audio interface circuit and the external electromagnetic interference. Electromagnetic interference discrimination methods are as follows; let the classroom megaphone and all electrical appliances are working, and the same with electrical appliances, which turn off without noise, is corresponding to the electric appliances caused by repair or resection. Otherwise it is second. As the noise; the humming sound in the interface circuit, the other is the interference of sound the conditions can be caused. Using the oscilloscope waveform. Look for reference.
From what you say, you are using a wired microphone, and I think other electrical appliances are interfering with the amplifier's signal amplification. Switch off other appliances. In this way, the shielding of the next amplifier is enhanced
The teaching amplifier is a megaphone which is mainly used for teaching by teachers. It is divided into two major categories, one is waist hanging, shoulder hanging type teaching amplifier, and the other is wireless teaching amplifier. The correct method of use is as follows:1 amplifiers should avoid the use of microphone on the horn, adjust the volume right clear, so to avoid distortion and feedback howling phenomenon.2., do not pull, drag and wring the microphone line, otherwise it will lead to poor contact between the wires.3., the host battery should not charge too long, over discharge, low battery prompt should be charged.4., summer and winter vacation when unused, should pay attention to one or two months charge.5., long-term should not let the battery discharge finished.6., if not used for a long time, should be placed in ventilated, dry, away from the heat source, magnetic field.
The reason why radio teaching amplifiers always make noise is that..:1, is the audio input plug, there is poor contact;2, the internal resistance is increased;3, it is outside electromagnetic interference.
