555 Timer and Tutorial (Popularity: )

An excellent extensive tutorial. Includes history, timing and logic diagrams. With numerous replacement guides.
Category: Science\Technology\Electronics\Reference

Sesp (UK) Ltd. (Popularity: )

Ultrasonic repellers and deterrents, and sonic repellers for to keep bird, animal, and insect pests ...
Category: Science\Technology\Acoustics, Ultrasound and Vibration\Ultrasound

Inventor's Association of New England (IANE) (Popularity: )

Located in Cambridge, MA.
Category: Science\Technology\Invention and Innovation\Organizations