Good Example Of Case Study On Security Alarm System

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Security alarm was being powered with 5volts supply making the system to demand for more power because of its high frequency. 5Volts uses 7400 series families where maximum and minimum volts can be accommodated using different units available within the series family. Considering the fact that voltage, current and temperature can all be varied with either low or high input values, 7400series families is commonly used. However, when designing a 12volts circuit, the 7400 series may not apply in this case. In some cases, +5V uses 7490 part numbers while +12V uses op-amp.
In order to design a +12V circuit design using NAND gates, IC HEF4011B NAND gates can be used because it accommodates high input and also produces high output. In case the wire is closed, a low input will be recorded but when is triggered, the NAND gate records a high input making the output high as well. The following components are required when designing a +12V digital logic. BC547 transistor, 1N4007 diode, 1kΩ resistor, 4.7kΩ resistor, 0.1µF Capacitor, relay, HEF4011B NAND gate. The NAND gate is a quad 2 input type that have a fully buffered output to eliminate noise and insensitive patterns impedance. The voltage range that can be handled by 011B NAND gate is +5V to +15V.
Figure 1.0 +12V Security Alarm System
In this project, Quad 2 input NAND gate has been used to ensure that the output is buffered for pattern insensitivity and noise immunity. The diode goes on when the circuit is complete.