Chapter-16: Basic Electronics

Electronics is that branch of applied physics which deals with the control of motion of electrons using different devices. Electronic devices being more effective and reliable have revolutionized the fields of telecommunication and information technology. This chapter providing: 

• explain the process of thermionic emission emitted from a filament. 
• describe the simple construction and use of an electron gun as a source of electronic beam. 
• describe the effect of electric field on an electron beam. 
• describe the effect of magnetic field on an electron beam. 
• describe the basic principle of CRO and make a list of its uses. 
• differentiate between analogue and digital electronics. 
• state the basic operations of digital electronics. 
• identify and draw the symbols for the logic gates (NOT, OR, AND, NOR and NAND). 
• state the action of the logic gates in truth table form. 
• describe the simple uses of logic gates. 

Short Question Answer
Q-1:	How digital electronic devices work?
Ans:	Digital electronics devices store and process bites electronically.
Q-2:	Give the examples of cathode ray tubes from you daily life?
Ans:	The picture in our T.V. set and display terminal of most computes are cathode ray tubes.
Q-3:	Name two factors which can enhance thermionic emission?
Ans:	i. Increasing strength of the battery and voltage. ii. By increasing temperature.
Q-4:	What are digital quantities?
Ans:	Digital quantities. Quantities whose values vary in non-continuous manner are called digital quantities. Digital quantities are expressed in form of digits or numbers.
Q-5:	In oscilloscope how filament is heated.
Ans:	In oscilloscope filament is heated electrically. When filament is connected to voltage source, current passes through filament and get heated.
Q-6:	What are the values of Boolean variables?
Ans:	Boolean variables can have only two values 0 and 1
Q-7:	What is meant by Boolean algebra?
Ans:	It is a branch of mathematics which deals with the relationships of logic variables.
Q-8:	Define analogy quantities.
Ans:	Quantities whose values very in continuously or remain constant are known as analogue quantities. Example: Temperature, time, pressure, distance and analogue quantities.
Q-9:	Name some use of oscilloscope.
Ans:	i. Displaying wave forms. ii. Range finding iii. Measuring voltages. iv. Echo sounding. v. Displaying heartbeats
Q-10:	Write some benefits of using digital electronic over analogue electronic.
Ans:	i. There is no interference in digital signal ii. Its easy to read digital quantities.
Q-11:	What is the use of grid in cathode ray oscilloscope?
Ans:	In the electron gun the grid is used to control the flow of electron, thus control brightness on fluorescent screen.
Q-12:	NAND gate is the reciprocal of AND gate discuss.
Ans:	NAND gate is formed when AND& NOT gate are connected one after the other .If AND gate show 0 output, then NAND gate will show 1 output. So we can say NAND agate is reciprocal of AND gate
Q-12:	What is cathode ray oscilloscope?
Ans:	An instrument which is used to display the magnitude of rapidly changing electric current or potential.
Q-13:	What is a cathode ray tube?
Ans:	A vacuum tube used to accelerate electrons which emit from the cathode by applying high voltage between cathode and anode is called ray tube.
Q-14:	What is the use of electron gun?
Ans:	It is used to investigate the properties of electron beam.
Q-15:	Why filament is heated?
Ans:	Filament is heated for emission of electrons. If metal is heated to a high temperature, some of free electrons may gain sufficient energy to escape metal surface.
Q-16:	Explain the uses of logic gates.
Ans:	Logic gates in electronic circuits are used to do useful tasks. These circuits usually use light depending resistors to keep inputs LOW. An LDR can act as a switch that is closed when illuminated by light and open in dark.
Q-17:	Why a large potential is applied between anode and cathode.
Ans:	A large potential is applied between anode and cathode to accelerate the beam of electrons.