Sunday, 28 February 2016

Electronic mailbox front door with ic 555



Living in the current rush to waste time to even have little value. Electronic circuits, so one is important in everyday life.Which saves time and convenience.
For example, this circuit. It gives us no time to wait to check voice mailbox.We see the LED is just enough.
Operation of the circuit. While no letter LDR will receive light from the lamp. The LDR resistance is very low. Resulting in IC does not work.
There is no output from the 3 pin. It make the current flows through R2, LED2 into three legs of IC1.The light LED2.But when a letter in the mail box to shield the light from the lamp. The LDR is not light. LDR will be much resistance.Voltage drop across the LDR is high enough to make IC1 work.
IC1 to produce frequencies from 3 pin. The light LED1

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