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许多人讨厌无休止的电视广告。采用下图电路,当广告到来时,用手指触摸一下触摸板,电视机的喇叭就断开,几十秒后(调1M电位器)广告结束或快要结束时,喇叭又自动接通,不至于漏掉下面的节目。该电路由于采用了通用接口电路555,因此极简单。其实用分立元件做一个触摸开关和一个延时器即可代替。555全称叫NE555,其它类似型号有553,558,559,556(2只555)。是双极型单片集成电路,国内上海元件5厂已试制成功。它可作可变延时;单稳态触发器;可调占空系数多谐振荡器1mS至几十小时可变程序定时器;频率合成;模/数变换;调相电路;数字取样及保持等,用途极广。国外许多电子刊物几乎每期都发表用555构成的各种实用电路。制作简单方便。它的内部原理图见图2,参数如下:
Many people hate endless television advertisements. Use the circuit below, when the ad comes, touch the touch pad with your finger, the TV speaker is disconnected, tens of seconds later (transfer 1M potentiometer) advertising end or near the end, the speaker automatically connected, not Miss the following program. This circuit is very simple because it uses the universal interface circuit 555. In fact, a discrete switch with a touch switch and a delay can be replaced. 555 full name is NE555, other similar models are 553,558,559,556 (2 555). Is a bipolar monolithic integrated circuit, the domestic Shanghai Component 5 plants have been successfully trial-produced. It can be used as a variable delay; monostable flip-flop; adjustable duty cycle multivibrator 1mS to dozens of hours variable program timer; frequency synthesis; A / D conversion; phase modulation circuit; digital sampling and maintaining A very wide range of uses. Many foreign electronic publications are published on almost every issue with 555 constitute a variety of practical circuits. Production is simple and convenient. Its internal schematic diagram shown in Figure 2, the parameters are as follows: