Table of Contents
How NAND gate is used in burglar alarm?
Burglar alarm or theft alarm It has a NAND gate with an LDR input. LDR means Light Dependent Resistor. When the alarm switch is closed, then one of the NAND gate inputs will be low. And if the LDR is kept in light, then the second input is also low.
Which gate is used in making burglar alarm?
Simple circuits made of up the different types of logic gates – NOT, OR, AND NOR, NAND, XOR, XNOR – can be used to perform simple and useful tasks. Because the circuits are simple and the logic gates are reliable and mass produced, the circuits are reliable.
What uses a NAND gate?
What are NAND gates used for? NAND gates help detect if a single input to a digital system has gone low. For example, a simple security system consisting only of NAND gates could be used to monitor the status of sensors connected to windows and/or doors.
How does NAND gate work?
In digital electronics, a NAND gate (NOT-AND) is a logic gate which produces an output which is false only if all its inputs are true; thus its output is complement to that of an AND gate. A LOW (0) output results only if all the inputs to the gate are HIGH (1); if any input is LOW (0), a HIGH (1) output results.
Which semiconductor device is used in burglar alarm systems?
Circuit Design of Burglar Alarm System The IR transmitter or IR LED is connected to a current limiting resistor of 150Ω and connected to supply. It is placed at the maximum possible range from photo diode. The cathode of the photo diode is connected to supply while anode is connected to 10KΩ resistor.
Why does the NAND gate become high when theft alarm rings?
So if any of the two situations occurs, the output of NAND gate becomes HIGH and then the theft alarm rings, as a sign of alert. The Burglar alarm is an electronic device which is used to detect the unauthorized entry, and as a security alarms and theft alarms.
What are the applications of LogLogic NAND gate?
Logic NAND gate has many applications like Burglar alarm, freezer buzzer etc. The burglar alarm circuit is shown below. It has a NAND gate with an LDR input. LDR means Light Dependent Resistor. When the alarm switch is closed, then one of the NAND gate inputs will be low.
How to design a NAND gate with two inputs?
From the truth table, it can be observed that NAND gate output will be high if any of its input is at low state. It will become HIGH if both the inputs are High. NAND gate can be designed by using transistors also.To design a 2 –input transistor NAND gate, we connect two resistors to bases of the two transistors.
Why does the thermistor on the NAND gate Buzz?
Since the NAND gate is connected as an INVERTER the output is LOW. As the thermistor warms up its resistance decreases, the voltage across it falls and the input to the NAND gate falls. When it becomes low enough the output becomes HIGH and the buzzer sounds.