I kindly request you for the introduction and the operation of the panic alarm.

Panic button

INTRODUCTION

A panic alarm is an electronic device designed to assist in alerting somebody in emergency situations where a threat to persons or property exists.
A panic alarm is frequently but not always controlled by a concealed panic alarm button. These buttons can be connected to a monitoring center or locally via a silent alarm or an audible bell/siren. The alarm can be used to request emergency assistance from local security, police or emergency services. Some systems can also activate closed-circuit television to record or assess the event.[1]

Alarm

A button in a critical system (such as a nuclear weapons system) used to quickly activate an extreme measure to mitigate an emergency situation.
A red button integral to key fobs which activates a car alarm's siren.
A device given to elderly individuals in order to maintain their independence outside of an Aged Care Facility, while still affording them a means of summoning help should they require it (i.e. a medical emergency that renders them immobile, like a fall, injury or illness). Such a device can also be referred to as an Emergency Medical Alert (EMA) button and can be fitted as either a pendant or bracelet to be worn by the user. MAB's are usually wireless connected to a call center. When the alarm is raised, an operator will call the individual's home to ensure a false alarm has not occurred; if there is no answer, the operator will alert either family members, emergency services, or both.
A button similar to the above, which is used indoors in self-sufficient houses for elderly people, where it alerts someone inside the house, who will then first check for a false alarm by phoning the person, and if there is no false alarm, will enter the person's flat to check what is the problem.
A button used in convenience stores, gas station, or other establishments staffed with a single employee during late hours. Often located under the counter near the cash register or safe, the button can be pressed in times of distress (Such as robbery, disruptive or threatening behavior, or a situation which may warrant assistance), triggering a silent alarm. If the button alarms a private security company, a fee may be charged for each time the button is used. This prevents misuse, and often aids in the employees judgment of the situation; whether or not it warrants the fee to have help to deal with the situation.

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Panic Alarm Circuit Diagram:

This circuit is made with a low cost hardware using IC 555 timer, buzzer, a few resistors and capacitors. It is made to be working reliably as it has simple to use and not so sensitive hardware like 555 timer, ceramic buzzer, capacitors, etc. Although no exclusive arrangement is used to make any compensation for the variable parameters, the circuit by default is made to be robust and easy to use. It is very user friendly with a single button to be pressed to handle the panicking situation without any trouble.