大多收音机都不具备无信号自动关机功能。许多收听者往往会忘记关电源而使得收音机整夜工作,白白浪费电能。如果给收音机加装一个无信号自动关机装置,那么深夜可放心收听,从而增加电池使用时间和延长收音机寿命。大多数收音机都有调谐指示灯,在收音机集成电路的调谐指示灯连接脚有信号时呈高电位,无信号时呈低电位,只要增加几个元件,利用此脚便可实现无信号自动关机功能。 Most radios do not have no signal automatic shutdown feature. Many listeners often forget to turn off the power and keep the radio working overnight, wasting power. If the radio is equipped with a signal-free automatic shutdown device, then late at night can be assured listening, thereby increasing battery life and extend radio life. Most radios have a tuning light, which is high when there is a signal on the tuner indicator of the radio IC. When there is no signal, it shows a low level. By adding a few components, the signal can be automatically shut down without any signal .