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...

Power Supply Rectification

Basic Power Supply Rectification Tutorial Many devices, in particular electronics, must use DC or direct current. A diode is a solid-state device that conducts in one direction...

How to connect batteries in Series-Parallel

How to connect batteries in Series-Parallel This is an introduction to how to properly connect batteries and cells in series or parallel for greater voltage or current. I'll...

Resistive Humidity Sensors

Resistive Humidity Sensors Resistive humidity sensors  measure the change in electrical impedance of a hygroscopic medium such as a conductive polymer, salt, or treated substrate. Photo...

How to Test a Diac

How to Test a Diac A diac is a two-electrode bidirectional avalanche diode which can be switched from off-state to the on-state for either polarity of the applied voltage. Again...

How Diodes and Rectifiers Operate

How Diodes and Rectifiers Operate A diode is an electrical device allowing current to move through it in one direction with far greater ease than in the other. The most...

Battery Applications

The table below shows the range of applications which use batteries together with typical battery capacities required by the application. The section on Battery Types outlines...