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日立CPT—2177SF/DU54cm(21英寸)遥控彩电,它是采用电子开关切换行振荡电源方式实现遥挖开机或关机。开/关机控制电路见图1所示。其工作原理是:当接通电源开关K,机芯主开关电源电路工作,一路主电源+B为110V通过T_(901)在C_(909)(220μF/160V)电容两端输出,加给行输出管Q_(781),另一路低压12V由T_(901)次级通过D_(904)整流,C_(915)滤波得到不稳定电压。此电压经R_(913)与ZD_(1101)稳压成5V(实测为
Hitachi CPT-2177SF / DU54cm (21 inches) remote control color TV, it is the use of electronic switching to switch the oscillation power supply way to achieve remote turn on or off. On / off control circuit shown in Figure 1. Its working principle is: When the power switch K is connected, the main switch power circuit of the movement works, all the way the main power + B is 110V, it is output to the C_ (909) (220μF / 160V) capacitor through T_ (901) Output tube Q_ (781), the other way low-voltage 12V by T_ (901) secondary through D_ (904) rectifier, C_ (915) filter to get the unstable voltage. This voltage is regulated by R_ (913) and ZD_ (1101) into 5V (measured as