GATE 2015 - Electrical Engineering

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Security System Switcher

An audio signal can be used as a form of input to control any security system. For example, an automatic security camera can be configured to respond to a knock on the door. The...

Water Pump Controller

A water pump controller senses the level of water in a tank and drives the water pump. The circuit described here is built around timer IC1 (555). When the water...

Battery-Low Indicator

Battery-Low Indicator   Rechargeable batteries should not be discharged below a certain voltage level. This lower voltage limit depends upon the type of the battery....

Over-Speed Indicator

This circuit is designed for indicating over-speed and direction of rotation of the motor used in mini hand tools, water pump motors, toys and other appliances.A 12V DC motor (M1)...

Simple Stereo Level Indicator

Usually, low-priced home stereo power amplifiers don’t have output level indicators. An output power level indicator can be added to each channel of these stereo power amplifiers....

Water level indicator

Here’s a simple water-level indicator for overhead tanks that uses three LEDs (LED1, LED2, and LED3) to indicate minimum, middle, and maximum water levels in the tank. The sensor...