Basic Electronics

Basic Electronics Kashif Bashir Email:kashif@pafkiet.edu.pk Web:http://www.Taleem.greatnow.com Kashif Bashir

Course Books!! • Text Books: • Basic Electronics (Eightth Edition) By Bernard Grob • Electronics Devices (Fifth edition) By Thomas L. Floyd Reference Book: • Introductory Electronic Devices And circuits By Robert T Paynter. Kashif Bashir

Marks Distribution!! 10% Project 10% Quizzes 5% Assignment 30% Hourly 40% Final Term Kashif Bashir

Survey of Electronics Int. to Basic Electronics Ohm’s Law Series Circuits Parallel Circuits Series-Parallel circuits Voltage Dividers and Current Dividers Kirchhoff’s Laws Alternating Voltage and Current Capacitance Int. to Semiconductors Diode Application Bipolar Junction Transistors Digital Electronics Course Description Kashif Bashir

Introduction • The name electronics comes form the electron, which is a very small, invisible particle of electricity present in all materials. • The fields of electronics name some main divisions. • Every type of electronic equipment makes use of solid-state semiconductor devices. The main factor in their operation is the ability to control the flow of electrons to obtain the desired elects. • An integrated circuit (IC) chip contains many transistors and diodes in one very small package. Kashif Bashir

Wireless Broadcasting • Broadcastingmeans to send out in all directions. The transmitter sends out electromagnetic radio waves radiated from its antenna. • Receivers can pick up the transmitted radio signal by means of a receiving antenna or aerial. The receiver reproduces the desired signal transmitted by the broadcast station. • There are many radio signals in space from different transmitters, but the receiver can be tuned to the frequency of the station we want. Kashif Bashir

Radio broadcasting b/w transmitter and receiver. An amplitude modulating (AM) carrier wave shown here Kashif Bashir

Radio Broadcast Services • Radio is an abbreviated form of radiotelegraph and radiotelephone. The word radio means radiation for wireless transmission. At first, communication was by radiotelegraph, using short dots and longer dashes in the Morse code. • The transmission distance for wireless communication can be less then a mile or as much as 5000miles, depending on the type of services • All radio services in the United states are regulated by the Federal Communications Commission (FCC). The FCC assigns the RF(radio frequency) carrier frequencies for transmission and monitors use of the airwaves. Kashif Bashir

Radio Applications • Standard AM Radio Broadcast Band. Amplitude modulation is used in transmission of the assigned RF carrier wave. Stations are assigned every 10 kHz in the band of 540 to 1700 kHz. • FM Radio Broadcast Band. This band is 88 to 108 MHz, with stations assigned every 200 kHz or 0.2 MHz. • Television Broadcasting. Television is just another application of wireless radio communications, but with picture information in addition to the sound signal. Two separate carrier waves are transmitted by the station in its assigned channel. One carrier is an AM picture signal, modulated by a video with the picture information. Kashif Bashir

Note: The total bandwidth required for AM can be determined from the bandwidth of the audio signal: BWt = 2 x BWm. Kashif Bashir

Figure 5-41 Amplitude Modulation Kashif Bashir

Figure 5-43 AM Band Allocation Kashif Bashir

Example We have an audio signal with a bandwidth of 4 KHz. What is the bandwidth needed if we modulate the signal using AM? Ignore FCC regulations. Solution An AM signal requires twice the bandwidth of the original signal: BW = 2 x 4 KHz = 8 KHz Kashif Bashir

Note: The total bandwidth required for FM can be determined from the bandwidth of the audio signal: BWt = 10 x BWm. Kashif Bashir

Figure 5-44 Frequency Modulation Kashif Bashir

Figure 5-46 FM Band Allocation Kashif Bashir

Example We have an audio signal with a bandwidth of 4 MHz. What is the bandwidth needed if we modulate the signal using FM? Ignore FCC regulations. Solution An FM signal requires 10 times the bandwidth of the original signal: BW = 10 x 4 MHz = 40 MHz Kashif Bashir

The other carrier is an FM sound signal modulated by the audio signal.A television channel is 6 MHz wide to include both the picture and sound signals for each broadcast station. Channel 2, for instance, is 54 to 60 MHz. • Amateur Radio. This field is one of the largest noncommercial radio services. Amateur radio operators, or “hams” usually build and operate their own transmitters and receivers to call one another in one of the assigned bands. A popular band 7 to 7.3 MHz. Kashif Bashir

Application of Electronics Three logical groupings of electronics applications are defined here. • Communications electronics. This field includes AM radio, FM radio with stereo, television with color. The equipment is divided between transmitters and receivers. • Satellite communications is also a transmit-receive system using electromagnetic radio waves. The satellite just happens to be orbiting around the earth at a height of about 22.300 miles in order to maintain a stationary position relative to the earth. Kashif Bashir

Geosynchronous Orbit Kashif Bashir

Electric Power. These applications are in the generation and distribution of 60-Hz ac power, as the source of energy for electrical equipment. Included are lighting, heating, motors, and generators. • Digital electronics. The circuits for digital applications operate with pulses of voltage or current. A pulse waveform is either completely ON or OFF because of the sudden changes in amplitude. In-between values have no function. Kashif Bashir

Electronic Components • Semiconductors. • Diode rectifiers • transistor amplifiers (either as separate, discrete components or as part of an IC chip. • Electron tubes: vacuum-tube diodes, amplifiers, and the cathode-ray tube (CRT) for a visual display device. A glass envelope en-closes the required electrodes in a vacuum. • Visual display devices. CRT , solid-state types of displays (light-emitting diode (LED) and liquid-crystal display (LCD)). • Resistors. 5. Capacitors or condensers. 6. Inductors or coils. Kashif Bashir

Digital Logic Gates One of the most common types of digital circuits is the logic gate. Its function is to allow only certain combinations of input pulses to activate the circuit. Logic gates are used in just about all-digital applications such as calculators, computers, and clocks, to name just a few. Kashif Bashir

Basic Electronics