Though the reliability of brain scanning for lie detection is still under question, these tests are fast becoming popular with the crime investigating teams....

Here’s the circuit of a multi-switch input musical doorbell (shown in Fig.1). The circuit is built around the popular and less expensive quad D-latch...

This circuit (Fig. 1), used in conjunction with a thin piezoelectric plate,senses the vibration generated on knocking a surface (such as a door or...

Here are two night lamp circuits using LEDs. One could be used as a night-vision clock and the other as a TV lamp. Both...

Won’t it be nice to have music playing in the background all the while when you take a shower? This simple circuit does the...

In small towns, there are no traffic lights and the police regulate the traffic with hand signals. Since their hand signals may not be...

This simple traffic controller can be used to teach children rudiments of traffic rules. The circuit (shown in Fig. 1) uses readily available components. It...

Electric kettles turn off automatically when water has boiled. What if the boiler beeps to alert you when your water has boiled? The tripping...

Electrical appliances like refrigerators and air-conditioners consume heavy current if the line voltage drops during the peak hours between 6 pm and 9 pm....

This is a new type of touch alarm that uses an RF oscillator at its input. One special feature of this touch alarm is...