This sensitive three-transistor circuit was found in Electronics Now magazine and is earphone-readable. The tuned range depends on the coil.
This circuit warms a light bulb slightly so that the wind through it alters the filament...
This circuit is based on the Linear Technology LT1495 and was found in a 2005 manual. The circuit...
The circuit illustrated in the figure can be used to detect earthquakes or vibrations of...