This simple circuit of a duophone allows you to access two telephone lines through one telephone set. Each telephone conversation will remain entirely separate...
An illuminance of 100 to 1000 lux is required for reading and doing close work without eye-strain. Specular illumination or bright sunlight provides 50,000...
Here is an ultra-sensitive fire sensor that exploits the direct piezoelectric property of an ordinary piezo element to detect fire. The lead zirconate titanate...
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...