Electronic timer switch circuit

Published:2011/6/27 2:52:00 Author:Fiona | Keyword: Electronic timer, switch | From:SeekIC

Close the power switch sA,the LED vD2 indicates the work,reduces the voltage by limiting resistor R2 and capacitance c1,rectifys by diode VD3,then filters by balanced symmetrical capacitance c2—c7 and obtains the 6v DC voltage in C7 ends.Because the backward resistance of the emitter junction is large and the input resisters of transistors VTl,VT2,VT3 are connected,The resistance is also very large,so this circuit can increase regular time.When turn on the power,the capacitor c8's voltage is Uc8 = oV, vTl, vT2, VT3 are cut off.vT4 provides the constant charging electric current to C8to make the Uc8 hasten linear growth.



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