Spy Ear
What binoculars do to improve your vision, this personal sound enhancer circuit does for listening. This light-weight spy ear gadget produces an adjustable gain...
Stereo Brick Amplifier
If you are looking for a compact and inexpensive add-on audio amplifier for your digital surround sound system or computer, then this subwoofer amplifier...
Green LED Flashlight with 555 Timer
Here is a simple green LED flashlight built around a 555 timer IC (IC1) and powered from a 3V battery pack.
Green LED-based flashlights are...
SMF Battery Guard
The emergency light is an automatic system in which a rechargeable battery-operated light source turns on as soon as the mains power fails. When...
Ball Speed Checker
This ball speed checker circuit measures the speed of a cricket ball based on the time taken by the ball to travel the distance...
Four Stage FM Transmitter
This four stage FM transmitter circuit uses four radio frequency stages: a VHF oscillator built around transistor BF494 (T1), a preamplifier built around transistor...
Metal Detector Circuit Using Difference Resonator
Described here is a simple metal detector circuit that can detect metallic conductors in its vicinity up to a range of 25 to 30...
Digital Camera Adaptor
You need not be disappointed next time your digital camera shows low battery indication during a picnic trip. Just plug this digital camera adaptor...
Programmable Electronic Dice
Here’s a simple programmable electronic dice with numeric display. This dice can be programmed using a 4-way DIP switch to display any random number...
Electric Fly Swatter
None of us likes bugs at home. To kill these flying insects, they should first be attracted and then electrocuted. An electric fly swatter...
