1. Principles of Telecommunications Technology Chapter 2

2. Objectives In this chapter, you will: Describe the principles of electricity that underlie all telecommunications signaling Explain the concepts of current and voltage as they apply to telecommunications technology Describe the components on an integrated circuit Explain the difference between analog and digital transmission Use binary encoding to represent decimal numbers Describe various electricity and data transmission measurements 4/26/2015 2 Modified by : Brierley

3. Atomic Charges Charge - the characteristic of a material that enables it to exert force on another material. Neutrons - found at the center of an atom, possess no charge and are said to be neutral. Protons - found at the center of an atom along with neutrons, carry a positive charge. Electrons - orbit the center of an atom and carry a negative charge 4/26/2015 3 Modified by : Brierley

4. Atomic Charges 4/26/2015 4 Modified by : Brierley

5. Static Electricity Static electricity - the release of an accumulated charge in some material or object. Because the charges inherent in electrons and protons are bound to balance each other through static electricity, these charges are also called electrostatic charges. 4/26/2015 5 Modified by : Brierley

6. Electric Current Electric current - the controlled movement of an electrical charge (or electrons) along the atoms of a conductor. Circuit - a closed connection between an electric source (such as a battery) and a load (such as a lamp) over which current may flow. Signal - occurs when current manipulated to transmit information. 4/26/2015 6 Modified by : Brierley

7. Electric Current Voltage - the pressure that the electric current exerts on its conductor is known. It is commonly equated to the strength of the electric current, and is measured in volts Amperes - the amount of current (or charge flowing through a wire each second ) is measured in amperes, abbreviated as amps. Resistance - a material’s opposition to electric current. 4/26/2015 7 Modified by : Brierley

8. Electric Current 4/26/2015 8 Modified by : Brierley

9. Conductors and Insulators Conductor - a material over which electric current readily flows. Grounding - the use of a conductor (such as a wire) to divert unused or potentially harmful charges to an insulator, where they will be stopped or absorbed. Insulators - materials that do not allow electric current to flow easily. Semiconductor - conducts electricity better than an insulator, but not as well as a conductor. 4/26/2015 9 Modified by : Brierley

10. Conductors and Insulators 4/26/2015 10 Modified by : Brierley

11. Resistance 4/26/2015 11 Modified by : Brierley

12. Calculating Voltage, Amps, and Resistance with Ohm’s Law 4/26/2015 12 Modified by : Brierley

13. Direct and Alternating Current Direct current (DC) - an electrical charge flows steadily in one direction over the conductor. 4/26/2015 13 Modified by : Brierley

14. Direct and Alternating Current Alternating current (AC) - the electrical charge flows in one direction first, then in the opposite direction, then back in the first direction, and so on, in an alternating fashion over the conductor. 4/26/2015 14 Modified by : Brierley

15. Direct and Alternating Current 4/26/2015 15 Modified by : Brierley

16. Direct and Alternating Current 4/26/2015 16 Modified by : Brierley

17. Capacitance The ability for an electric circuit or component to accumulate or store a charge. Capacitance is measured in Farads (abbreviated as F), a unit named after English chemist and physicist Michael Faraday, who experimented with electricity in the early 1800s. Capacitor - a device that stores electrical charge (as the tank stores water). 4/26/2015 17 Modified by : Brierley

18. Capacitance 4/26/2015 18 Modified by : Brierley

19. Capacitance 4/26/2015 19 Modified by : Brierley

20. Capacitance 4/26/2015 20 Modified by : Brierley

21. Capacitance 4/26/2015 21 Modified by : Brierley

22. Inductance 4/26/2015 22 Modified by : Brierley

23. Inductance 4/26/2015 23 Modified by : Brierley

24. Inductance 4/26/2015 24 Modified by : Brierley

25. Inductance 4/26/2015 25 Modified by : Brierley

26. Inductance 4/26/2015 26 Modified by : Brierley

27. Inductance 4/26/2015 27 Modified by : Brierley

28. Electrical Power 4/26/2015 28 Modified by : Brierley

29. Electrical Power 4/26/2015 29 Modified by : Brierley

30. Measuring Electricity 4/26/2015 30 Modified by : Brierley

31. Measuring Electricity 4/26/2015 31 Modified by : Brierley

32. Measuring Electricity 4/26/2015 32 Modified by : Brierley

33. Passive Electronic Devices Passive device - a component that contributes no power gain to a circuit. Resistor - a component inserted into a circuit to provide a specific amount of resistance 4/26/2015 33 Modified by : Brierley

34. Diodes 4/26/2015 34 Modified by : Brierley

35. Diodes 4/26/2015 35 Modified by : Brierley

36. Transistors 4/26/2015 36 Modified by : Brierley

37. Integrated Circuits Circuits that combine the conductor and the attached components of a circuit in one small unit. 4/26/2015 37 Modified by : Brierley

38. Analog Transmission Analog - electromagnetic signals that continuously vary in their strength and speed. 4/26/2015 38 Modified by : Brierley

39. Transmission Flaws Noise - unwanted interference from external sources, which can degrade or distort a signal. Attenuation - the loss of a signal’s strength as it travels away from its source. Amplifier - an electronic device that increases the voltage, or power, of the signals. Regeneration - when digital signals are repeated, they are actually retransmitted in their original, pure form, without any noise. Repeater - a device that regenerates a digital signal. 4/26/2015 39 Modified by : Brierley

40. Transmission Flaws 4/26/2015 40 Modified by : Brierley

41. Transmission Flaws 4/26/2015 41 Modified by : Brierley

42. Encoding and the Numbering System Encoding - the process of modifying data so that it can be interpreted by the receiver. Methods for encoding data include: The Decimal System The Binary System Hexadecimal System EBCDIC ASCII UNICODE 4/26/2015 42 Modified by : Brierley

43. Measuring Data 4/26/2015 43 Modified by : Brierley

44. Throughput and Bandwidth Throughput - the amount of data that a communications channel can carry during a given period of time. The physical nature of every communications channel determines its potential throughput. Bandwidth - a measure of the difference between the highest and lowest frequencies that a media can transmit. 4/26/2015 44 Modified by : Brierley

45. Summary Electricity may exist as either static electricity, the imbalance of charges, or as current electricity, the flow of charge along a conductor. The three main characteristics of a circuit are voltage, current, and resistance. If two of these characteristics are known, the third can be calculated using Ohm’s Law. Electronic devices may be active or passive. Examples of passive devices are capacitors and inductors. Examples of active devices are transistors and diodes. 4/26/2015 45 Modified by : Brierley

46. Telecommunications Principles END 4/26/2015 46 Modified by : Brierley