This is automatic light circuit when be become dark. It by use LED Lamp, be a place gives the light and this circuit has small-sized use volt supply 3V only.
The work of the circuit be when there is the light affects LDR1 will valuable the resistance at LDR1. It be down make Q1 work be born volt at fall straddle a pin C of Q1 compare with Ground be valuable a little more voltage bias to make Q2 work. By have D1 serial with a pin B of Q2 make volt at pin C of Q1 compare with ground must use volt about 1.4V arrive at make Q2 work. But when LDR1 no the light will make to is valuable the resistance more and more until make to have no current flow get along well with B of Q1 make Q1 do not work. Then have current flow through R1,D1 get along well with pin B of Q2 work cause LED1 stick bright. The part , VR1 , parallel connection with , LDR1 , as a result , for take keep fine the rapidity in taking light of LDR1
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This entry was posted on Saturday, May 1st, 2010 at 11:36 pm and is filed under Electronic Control, Lighting.
