i want the concultion on electronic letter box .....plz show me the conclution
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When the letter drops by someone in the mailbox, the LED connected to the output stops blinking, indicating that there is a letter in your mailbox. To identify the presence of a letter in the box we have connected an LDR as well as a light source. LDR is a special type of resistance whose action is based on the intensity of the light decreasing in it. In the time of total darkness the LDR resistance is approximately 1 mega ohm while at the time of bright light its resistance is 2-5 ohms. In this circuit the light source is adjusted with the LDR in such a way that the light will fall directly into the LDR so that when any letter enters the mailbox, the light fragment will fragment and the LDR will be under the darkness.
Electronic circuit diagram of the letter box:
Circuit Components:
• IC
• LM741-1
• CD4001-1
• Resistors
• R1 (2.2M) - 1
• R2 (560K) - 1
• R 3, R 4, R 5 (1 K) -3
• R6 (220k) - 1
• R7 (220E) - 1
• C1, C2 (.1uF) - 2
• Various
• LED1 - 2
• Vr1 (10K) - 1
• LDR - 1
Component Description:
• LDR - It is a device whose sensitivity is based on the intensity of the inclination of the light in it. With the increase in the force of the light, the resistance of the LDR decreases and vice versa. When there is no light or in the dark, the resistance of LDR reveals in the range of mega ohms, while in the presence of light they move a few hundred.
• LED - Consists of semiconductor that produces several colors of light as its output. The LED produces a narrow spectrum light at the moment it is electrically biased at the junction p-n in the forward bias state. When in the ignition mode, it combines the electrons with the holes and in the form of light energy release.
• LM741 - It is basically a multifunctional operational amplifier that is basically used to improve circuit performance above industry standards. They are direct plug-in replacement for the IC like 709C, LM210 also for MC1439, as well as 748 in many applications. There are many applications that make it almost infallible. One is the overload protector at the input and output. Another is the non blocking at the time of common mode range is to go beyond and independent of the oscillation.
• Resistance - The resistor is connected to any circuit to restrict current flow. There are two varieties of resistances that are mentioned below.
• Fixed Resistance - Its resistance value is fixed.
• Resistance Variable - Its resistance value may vary. Suppose we have 5K resistance then its value varies from 0-5K ohms.