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这是一只低价的晶体管定时器电路,可以在设定时间内自动切断电视机等家用电器,并同时发出声光告警。电源供给电压为12V,电流300mA。 自动断电的设定时间通过调整VR1可在几分钟至半小时范围内变化。电源接好后可短时按下启动开关S1,这时T1、T2、T3均导通,RL1吸合,家用电器负载通过N/O接N220V交流电源,表示电器工作的绿色指示灯LED1
This is a low-cost transistor timer circuit, you can automatically cut off the TV and other home appliances within the set time, and at the same time audible and visual alarm. Power supply voltage of 12V, current 300mA. The setting time for automatic power-off can be changed within a few minutes to half an hour by adjusting VR1. After the power is connected, the start switch S1 can be pressed for a short time. At this time, T1, T2 and T3 are both on and RL1 is on. The load of household appliances is connected to the N220V AC power via N / O, indicating that the green indicator LED1