e can't look too far these days without encountering some form of electronics Whether they are used to entertain us operate machinery or perform complex calculations electronics play a significant role in our lives And it seems there's no end in sight to fasci nating new innovations This book provides an overview of the many different kinds of electronics how they work how we use them and the history of their development Electronics are such a common part of our lives that we rarely stop to think about how they work The branch of physics we Pla know as electronics deals with the produc tion behavior and effects of electrons and I with electronic devices Electronics is espe cially concerned with how transistors and electron tubes are used in electronic devices Two basic types of electronic signals ana log and digital are made up of electric current that indicates information Digital signals are the most commonly usedbyelectronic devices Semiconductors materials that conduct elec tricity under certain conditions manipulate both analog and digital signals The transistor MEN is the basic type of semiconductor device In Now K
INTRODUCTION 1947 William B Shockley Walter H Brattain and John Bardeen invented the transistor which replaced the vacuum or electron tube in many devices Operations by all computers and complex electronic equipment result from combina tions of circuits These circuits supply the conduit for the electric currents that power such devices Today's circuits are smaller than ever which makes microprocessors possible Transistors and other semiconductors work with other elements to perform a vast vari ety of functions The central elements are resistors which slow down electron flow and in control voltages and currents conductors which work as connectors between circuits or circuit elements and capacitors which In store electrical charges Rather than being I Rus Del made up of multiple individual parts today s electronics have millions of tiny circuits of 13 l implanted on a tiny integrated circuit IC The tiny but often powerful micro processor is a little computer made up of semiconductor chips It originated with the electronic computer but microproces sors can be found in video games security systems and calculators to name just a
ELECTRONICs Improvements in how they are manufactured have made the chips more readily available Modern electronic devices are almost everywhere we look Consumers started out using electronics in their phonographs but now the field has expanded to satel lite radios MP3 players and even tablet computers that use a touch screen for a key board Of course electronics are not only for home use Medicine is just one field that takes advantage of electronics all the time Doctors can get a more detailed look at the human body by using diagnostic instruments such as computed tomography CT and nuclear magnetic resonance NMR scan ners Transportation whether by road air or spaceſ also relies heavily on electronics Experiments in the late 19th and early 20th centuries by several inventors had dramatic effects Thomas Edison's 1883 dis covery of thermionic emission discharge of electrons from heated materials eventually resulted in the radio tube A few years later in 1887 Heinrich Hertz stumbled upon the pho toelectric effect in which charged particles are released from a material when it absorbs radiant energy a discovery that led to pho toelectric cells In 1904 John A Fleming 10 MILE 8
INTRODUCTION invented the Fleming valve now known as a diode The triode an electron tube consist ing of three electrodes would come about in 1906 when Lee De Forest adapted the diode I The vacuum tube led to the development of radio television and electronic computers There 1s no denying our reliance on elec tronics from the lights that illuminate our houses to complex computers that direct space probes as they hurtle through space Could more highly developed electronics come about This overview of electronics shows that there are no limits to how they can progress and change our lives Umm Umm Am I Am TTI HUI
