Most darkness activated alarms employ opamps and some logic ICs. Here, a less expensive approach is shown based on the eternal 555, this time in monostable multivibrator mode. Components R2 and C1 represent a one-second network. When the LDR (light dependent resistor) is in the dark, its resistance is high, pulling pin 2 of the [...]
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 [...]
Today we come to see the circuit detects the light by have a voice warn. When meet the light or be become dark depend on using S1 ( follow the circuit ). For this my circuit uses the integrated circuit IC 555 be pillar equipment again. You can choose can use many the number be [...]
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