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本定时器顺计时设置的时间为1min～23h 59min;逆计时设置为59min～1min。尤其是使用电吹风、电熨斗时,即使不设置定时,只要置于数字钟档的位置,都可以预防因市电突然断电、中途又恢复供电后引发火灾的危险。 顺计时电路工作原理:电路原理见附图,接上电源,按下SB接通电源,220V市电经变压器T降压、VC整流、C_1滤波后,输出一直流电压。该直流电源通过电阻R_3流过继电器K绕组,回到电源负端,形成一电源回路,继电器K得电吸合,触点K_(-1)吸合自锁。由于晶闸管VS的G极没有触发电流而处于截止
The timer is set in time clockwise 1min ~ 23h 59min; reverse timing is set to 59min ~ 1min. Especially when using hair dryers and electric irons, you can prevent the risk of a fire caused by a sudden power failure in the mains and the resumption of power supply after the power is turned on even if you do not set the timing. Shun timing circuit works: The circuit principle see attached drawings, connected to the power, press the SB power, 220V mains by the transformer T buck, VC rectifier, C_1 filter, the output of a DC voltage. The DC power flows through the resistor K winding through the resistor R_3 and returns to the negative terminal of the power supply to form a power circuit. The relay K is electrically connected and the contact K_ (- 1) is self-locking. Because the gate of the thyristor VS G does not trigger the current and in the cut-off