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Electronic mailbox front door with ic 555

This entry was posted on Wednesday, September 8th, 2010 at 5:56 pm and is filed under 555, Electronic Control, detector. 

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.

source : eleccircuit.com

Switch volume control by op-amp IC

  

Switch press added – reduced pressure
This circuit IC1 is IC op amp circuit connected to an Integrator circuit. Operation of the circuit. When the press switch S1 will have positive current flow from the power supply Through resistor R1 to charge the capacitor C2. As a result the output of IC1, lower voltage to 0 volts. When the switch press switch S2, the voltage output level of IC1 is back. Increase nearly as quickly or until the supply voltage. When the buffer circuit IC1.Therefore, voltage output of IC1 is how much value will be passed to IC2 and the output voltage (Vout) that you want.