Question { BSNL, 7667 }

what are advantages of pwm over simple supply?

Answer

pwm-pulse width modulation
             advantages
1,better efficiency than power supply(since,transistor is working in cut-off and saturation only)
2,decrease in size and cost(since,the high operating frequency used for switching transistors allows to use of smaller transformers,capacitors,and inductors)

Question { Infosys, 6019 }

what is race around condition?
in which flop it will occur?
how to remove?

Answer

when J=K=1,
the out put toggles 
ie there is uncertainity in the out put (since, time period of cloak>>time petiod of propagation delay)
this can be avoided by 
1,MASTER SLAVE JK-FF
2,Edge Triggerring

Question { 4291 }

How do you calculate the amount of feedback given in a
negative feedback
amplifier ? Illustrate

Answer

A/(1+AB)

Question { 3636 }

What is frequency response actually? What is its importance in
the field of electronics or communication?

Answer

the curve between voltage gain and signal frequency of an amplifier is known as frequency response