Basic Electronics Objective Questions:


Que 1. When a PN Junction is formed, diffusion current causes

1) mixing of current carriers
2) forward bias
3) reverse bias
4) barrier potential

Ans: 4

Que 2. Pure Semiconductor Silicon Doped with Boron forms

1) pn Type Semiconductor
2) n type Semiconductor
3) p type Semiconductor
4) np type Semiconductor

Ans: 3

Que 3. Wider Band gap Semiconductors are called:

1) Super conductor
2) Super Isolators
3) Semi Semiconductors
4) Semi Isolators

Ans: 4

Que 4. Which of the following is common feature of FET
   
1) They have high input impedance   
2) These are voltage controlled devices  
3) They have isolated input & output     
4) All of these

Ans: 4

Que 5. In a pn diode, hole diffuse from p region to n region because

1) there is high concentration of holes in the p region 
2) holes are positively charged
3) holes are urged to move by the barrier potential
4) the free electrons in the n region attract the holes.

Ans: 1

Que 6. If you need to design a relaxation oscillator circuit. The most likely device to use might be

1) a SCR
2) a UJT
3) a Triac
4) All of these

Ans: 2

Que 7. The ripple factor of a power supply is a measure of

1) its filter efficiency
2) its voltage regulation
3) diode rating
4) purity of power output

Ans: 1

Que 8. The maximum number of electrons which the valence shell of an atom can have is __      

1) 6A
2) 8A
3) 18A
4) 2A

Ans: 2

Que 9. Doping materials are called impurities because they

1) decrease the number of charge carriers
2) change the chemical properties of semiconductors
3) make semiconductors less than 100 percent pure
4) alter the crystal structures of pure semiconductors

Ans: 4

Que 10. In a PNPN diode, breakover condition is marked by

1) a sudden decrease in current     
2) a sudden increase in current    
3) diode getting burnt off  
4) a sudden glow taking place
 
Ans: 2
    

Que 11. In an PN junction depletion layer is created due to
     
1) Diffusion of ions
2) Diffusion of Minority carriers
3) Diffusion of Majority carriers
4) Diffusion of Minority & Majority carriers

Ans: 3

Que 12. In a schmitt Trigger UTP=12V, LTP=8V, the hysterisis VH is

1) 12V
2) 8V
3) 4V
4) 20V

Ans: 3

Que 13. In a transistor, ß may be expressed in terms of a as below:

1) a/1a
2) a/1+a
3) 1+a/a
4) 1a/a

Ans: 1
 

Que 14. A semiconductor has _________ temperature coefficient of resistance

1) Positive
2) Zero
3) Negative
4) None of these

Ans: 3

Que 15. Laser is a
 
1) Light Source
2) Light Detector
3) Both Light Source & Light Detector   
4) None of these
  
Ans: 1
 

Que 16. Laser Light is different from others because

1) It is Coherent 
2) It is incoherent
3) High Intensity
4) High Speed

Ans: 1

Que 17. The cause of potential barrier in an pn junction diode is
      
1) Depletion of positive charge near the junction
2) Concentration of positive charge near the junction     
3) Depletion of negative charge near the junction      
4) Concentration of positive and negative charge near the junction
       
Ans: 4
 

Que 18. A transistor in common emitter mode has
     
1) a high input resistance and a high output resistance
2) a very low input resistance and a low output resistance       
3) a medium input resistance and high output resistance     
4) a high input resistance and low output resistance
     
Ans: 4

Que 19. Thermal runaway in BJT will take place if the quiescent point is such that
           
1) Vce > 1/2 Vcc
2) Vce
3) Vce < 2Vcc
4) Vce < 1/2Vcc

Ans: 4

Que 20. N Type silicon is obtained by doping silicon with N

1) Germanium
2) Gallium
3) Phosphorous
4) Boron

Ans: 3

Que 21. The main drawback of JFET is its :

1) high input impedance 
2) low input impedance 
3) higher noise
4) lower gain

Ans: 4

Que 22. A semi conductor when placed at 0° K, will act as

1) Insulator
2) Conductor 
3) Semiconductor  
4) Metal

Ans: 1

Que 23. In a semiconductor, current conduction is due to,   _________    

1) Only holes
2) Only free electrons
3) Holes and free electrons  
4) None of these
  
Ans: 3

Que 25.The maximum efficiency of a half wave rectifier is __________  

1) 40.6%
2) 25%
3) 81.2%
4) 50%

Ans: 1

Que 26. In a UJT, intrinsic stand off ratio n is typically

1) 0.2
2) 0.4
3) 0.7
4) 0.99

Ans: 3

Que 27. An ideal diode

1) should have zero resistance in the forward bias as well as reverse bias         
2) should have zero resistance in the forward bias and infinitely large resistance in reverse bias            
3) should have infinitely large resistance in the forward bias and zero resistance in reverse bias            
4) should have infinitely large resistance in the forward bias as well as reverse bias
          
Ans: 2

Que 28. Schmitt trigger may be used to _________   

1) change voltage to corresponding frequency    
2) change frequency to voltage
3) change a slowly varying voltage to square voltage        
4) none of these
   
Ans: 3