Encyclopedia of electronic components volume 1 resistors capacitors inductors switches encoders relays transistors charles platt on amazoncom . Bionic contact lenses are being developed to provide a virtual display that could have a variety of uses from assisting the visually impaired to the video game . Most leds were made in the very common 5 mm t1 3 4 and 3 mm t1 packages but with rising power output it has grown increasingly necessary to shed excess heat to