The rapid development of electronics provides a secure environment to the human. As a part of this ‘ WOMAN SECURITY SYSTEM’ is designed to reduce the risk of accidents and will reduce the rate of rape. This system is composed of a Microcontroller and a GSM Modem.
This is an inexpensive device which reduces the problem associated with accident notification.
In this project-
Here we use ATMEL89C52 microcontroller. It mainly controls all function of the project. GSM modem is used to send messages to the predefined numbers stored in the microcontroller. This GSM modem uses commands in order to send messages to the predefined number.
A power supply is a major concern for every electronic device.Since the controller and other devices used are low power devices there is a need to step down the voltage and as well as rectify the output to convert the output to a constant dc.
A transformer is a device used to increment or decrement the input voltage given as per the requirement. The transformers are classified into two types depending upon there functionality.
- Step up transformer
- Step down transformer
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Here we use a step-down transformer for stepping down the household ac power supply i.e. the 230-240v power supply to 5 v.We use a 5-0-5 v center tapped step down transformer.
The output of the transformer is an ac and should be rectified to a constant dc for this it is necessary to feed the output of the transformer to a rectifier.
The rectifier is employed to convert the alternating as to a constant dc. There are many rectifiers available in the market some of them are:-
- Half wave rectifier
- Full wave rectifier
- Bridge rectifier
The rectification is done by using one or more diodes connected in series or parallel.
If only one diode is used then only first half cycle is rectified and it is termed as half wave rectification and the rectifier used is termed as Half wave rectifier. If two diodes are employed in parallel then both positive and negative half cycles are rectified and this is full wave rectification and the rectifier is termed as Full wave rectifier.
If the diodes are arranged in the form of the bridge then it is termed as Bridge rectifier, it acts as a full wave rectifier.