Design and Implementation of an Automatic Power Cutoff System Using Capacitors

This paper presents an innovative automatic power cutoff system designed to disconnect electrical devices from the AC mains supply after a user-configurable time delay. The system incorporates a Timer IC (such as the 555 Timer), which is configured in monostable mode to generate precise time delays based on the RC network consisting of a Farad capacitor and a variable resistor. This configuration allows users to adjust the delay duration as per their needs, making the system highly flexible and customizable. The system is particularly suited for applications where controlled power consumption is essential, such as in device charging or powering appliances for a specific period. The RC network enables customizable cutoff times, with adjustments ranging from a few seconds to several hours. This flexibility is particularly advantageous for energy-saving applications, where reducing unnecessary power consumption is critical. The use of a high-capacity Farad capacitor ensures that the system can support longer delays without compromising stability. Additionally, the system is designed for seamless integration into existing electrical circuits, with the entire setup implemented on a compact printed circuit board (PCB) for reliability and ease of use. The PCB layout has been carefully optimized to minimize electrical interference, which could otherwise affect the operation of the Timer IC and the relay switching mechanism. By using high-quality components and precise PCB design techniques, the system ensures smooth and consistent operation, even in environments with fluctuating power supplies. The relay, which serves as the main switching element, disconnects the load from the power supply once the timer reaches the pre-set cutoff duration, providing an additional layer of safety. Experimental results the system's effectiveness in energy-efficient applications, particularly in controlling power usage during device charging. The automatic cutoff feature helps prevent overcharging and unnecessary power drain, contributing to both energy conservation and extending the lifespan of connected devices. The system's reliability, ease of use, and configuration make it a valuable solution for a wide range of consumer electronics and home automation scenarios.