I was using a test board I designed to measure component level radiated emissions. During the measurements I started to suspect that some of the emissions were coming from the test board. The only ...

Figure 1 shows how a Sallen-Key high pass filter (HPF), can be switched on/off using only one extra transistor and resistor. Figure 1 A Sallen-Key HPF filter topology that can be switched on/off using ...

Researchers report development of a low-cost carbon filter that can remove 90 percent of carbon dioxide gas from the smokestacks of electric power plants that burn coal and other fossil fuels. The new ...

Field tests in Nepal suggest that people who live in areas with arsenic-tainted aquifers may be able to purify their drinking water by passing it through a low-cost, low-tech filter with a simple ...