140 likes | 347 Views
ELECTRONIC/COMPUTER AGE. Electronic/Computer Age. Electronics Electrical signals can carry information quickly over wires or through the air by radio Light, Appliances and Entertainment Atoms An atom is the tiniest part of a material There are only 109 elements known to exist
E N D
Electronic/Computer Age • Electronics • Electrical signals can carry information quickly over wires or through the air by radio • Light, Appliances and Entertainment • Atoms • An atom is the tiniest part of a material • There are only 109 elements known to exist • Compounds --- different kinds of atoms combined together, e.g. table salt, water etc • A compound has properties all its own • Atoms are made of smaller particles with their own properties • Protons and neutrons in the nucleus and electrons in the orbits circling the nucleus --- protons and electrons have diff. charges
Electronic/Computer Age • Electric Current • Materials whose atoms give up some electrons easily are conductors • Materials that hold tightly to their electrons are insulators • The flow of electrons is current --- Amperes • 1 amp = 6 billion billion electrons flowing past a point in 1 sec • Electromotive force makes a current flow --- Volts • A battery provides electromotive force • Resistance is the opposition to a flow of current --- Ohm’s law • V = IR or I = V/R
Electronic Components & Circuits • Electronic components or parts control the flow of electricity --- each component has its own symbol • Circuits --- different forms in which components are connected • Schematics --- drawings that show plans for circuits • A resistor is used to control the flow of current --- 0.1 – 106 • Color coded bands indicate the resistance in ohms • Semiconductors are neither good insulators or good conductors, e.g silicon • A diode is made using a semiconductor, it lets current flow in only one direction
Electronic Components & Circuits • Transistor • A resistor that lets a small amount of current control the flow of a much larger amount of current, e.g. motors, computers • It is a square wafer a few thousandths of an inch on a side • A thermistor has a resistance that changes with temperature • A photoresistor has a resistance that changes with the amount of light hitting it • Printed Circuits • Solder is a method of joining two wires together • Wires’ contact causes an unintended flow of current --- short circuit --- use of insulation • A printed circuit board is a thin board of an insulating material like fiberglass • The conducting paths are photographically placed over it
Electronic Components & Circuits • Once components are mounted on the board, they can be soldered by an automatic soldering machine • Integrated Circuits • It provides a complete circuit on a tiny bit of semiconductor • They are often less than 1/10th of an inch in length and width • The drawing of a chip is photographically reduced to form a mask • Chips have replaced large bulky circuits and are quite less in volume and price • Computers are built using large ICs • Analog and Digital Circuits • An analog circuit works with analog signals • In digital circuits, a voltage above a certain value is coded as a 1 and a voltage below that value is coded as a 0.