有關收音機""急急急!!20點!!!

剛發明的收音機，是用真空管為主要零件；
現在的是用原子粒及I.C.所製造，
所以，可愈出愈細部。

The radio principle is receive from the antenna to of high Pin signal through check the wave(solution adjust) restore the audio frequency signal, sending to headphones to become sound wave.Because the broadcast business develops, having the wireless electric wave of a lot of different frequencies in the sky.If all receive down this many electric waves, the audio frequency signal is placed in busy streets for the meeting elephant in similar, many voices mix together, result what also heard not pure.

   For trying choice the program needed, there is a selectivity electric circuit after receiving antenna, its function is need of the signal(radio station) choose, and do not want of the signal"the Lyu drop", so as not to produce interference, this is When we listen to broadcast, "choose pedestal" used button. The exportation of the selectivity electric circuit is the high Pin rate signal that selects a certain radio station, make use of it and pushes headphones(electricity voice machine) and do not go directly, have to also chase its instauration original audio frequency signal, this kind of revivification electric circuit is called solution to adjust, sending the audio frequency signal that the solution adjusts to the headphones, can receive broadcast.

   Is most simple what to speak up the radio be directly called to check wave machine, but from receives the high Pin antenna telecommunication number that the antenna gets generally very faintly, send it to the detector directly not that suitable, had better Be choosing of the electric circuit and detector to insert into a high Pin enlarger, enlarge high Pin signal.Even have already increased high Pin enlarger, check wave output's power usually also only several milli- tiles, hear with the headphones can also, but want to dislike with the loudspeaker to be too small, so increase the audio frequency enlarger after checking an exportation to push.