A previous Design Idea describes a circuit that uses an astable multivibrator to drive an LED (Reference 1). The circuit in Figure 1 uses a simpler alternative approach. The circuit uses a 2N3904 NPN ...

In the early days, PNP bipolar transistors were common, but the bulk of circuits you see today use NPN transistors. As [Aaron Danner] points out, many people think PNP transistors are “backward” but ...

Hacker [Dino Segovis] is back with yet another installment of his Hack a Week series, and it’s looking like he isn’t too worse for wear after hunkering down to face hurricane Irene. This week, it ...

A very simple but highly efficient combination lock circuit is shown in the figure. Any type of on/off switches can be used, varying from commercially available inexpensive types to more sophisticated ...

Thermocouples and their leads often have to detect open-circuit or short-circuit faults. However, it is very difficult to distinguish a valid millivolt temperature signal from an open/short-circuited ...

One secret to creating the world's fastest silicon-based flexible transistors: a very, very tiny knife. Engineers have now pioneered a unique method that could allow manufacturers to easily and ...