电话机靠振铃发出声音来提醒有电话打进,但对环境嘈杂很难听清振铃声或对听力低下的老年人及聋哑人来说,几乎起不到提醒作用。为此本文介绍一种简单易作的电话机视觉振铃器,能使来电话呼叫时,除电话机本身振铃发出声音外,红色灯泡也同时发光,使人能知道有电话打进。电话见图1。X1、X2并接于电话机进线盒上,无电话呼叫时,由于C1隔直C2两端无电压。当有电话呼叫时,在电话 The phone ringing sounds to remind the phone to get in, but the environment is noisy and difficult to hear the ringing of the elderly or hearing-impaired elderly and deaf-mutes, almost no reminder. To this end this article presents a simple and easy to operate visual ringer for telephone sets that enables incoming calls to ring, in addition to ringing the telephone itself, making the red light bulb shine at the same time so that one can know that a call has been made. See Figure 1 on the phone. X1, X2 and then connected to the phone into the terminal box, no phone call, as C2 across C1 without voltage across. When there is a phone call, on the phone