If you enter the physical world and open a door—say, to walk into a store—you will intuitively hold the door open if someone is walking behind you and you see them or hear them. Even if you aren’t ...

A delta wave, also known as delta rhythm, is the normal brainwave in the encephalogram of a person in deep, dreamless sleep, occurring with high voltage and low frequency (1 to 4 Hz). If you plan to ...

This two-transistor white noise generator has a surprising feature – about 30dB more noise than the more traditional designs. Q1 and Q2 can be any small-signal transistors with a beta of up to 400.