what is meant by peak inverse voltage

 what is meant by peak inverse voltage?

peak inverse voltage:- The maximum voltage that a diode can withstand in Reverse bias before it breakdown and this voltage is called as peak inverse voltage.

write the current equation in pn junction diode

 what is the current equation in pn junction diode?

why we use cascade connection

     what is use of cascade connection?

you can see the given figure is example of cascade system before going to why we need cascade let us know about what is meant by cascade  system. when output of one transistor is given as input to other transistor or series connection of transistors  is called cascade connection.
Now coming to the real question why we require cascade connection. Cascade system gives following advantages
1.It increases  the overall gain
2.Sometime the input impendence or output impendence will be different from what we want then we use cascade connection and make desired values

what is law of mass action or constancy of pn product

 Mass action law or constancy of pn product

It states that ,under thermal equilibrium the product of concentration of free electrons and concentration of free holes is constant and the value of constant is equal to square of intrinsic carrier concentration of that material 

        

                                         pn = ni²

                        where  p = hole concentration
                                    n= electron concentration
                                    ni=intrinsic carrier concentration

why npn transistor preferred over pnp transistor

 why npn transistor preferred over pnp transistor?

1.npn has elctrons as majority charge carriers whereas pnp transistor has holes as majority charge carriers.

We know that mobility of electrons are higher than mobility of holes so what is use of high mobility, high mobility can make transistor work properly at higher frequency. So  npn transistor is used so that it can work properly even at higher frequency when compare to pnp transistor.

2.npn transistor is most suitable for negative grounding. 

 

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why we neglect interelectrode capacitance of a transistor device when it is working at low frequency

 why we neglect interelectrode capacitance in of transistor at low frequency?

  we know that reactance of capacitor is 

Xc=1/j(wc)

where w is angular frequency 

As frequency is very small the angular frequency (w) will also be very small ( f=2πw).

let w → 0  ( w tends to zero)

 Xc→∞

( anything divided by small value gives a large value)

so Xc is very high means the resistance offered by the capacitor is very large so capacitor act as open circuit

(open circuit contains infinite resistance so capacitor behaves as open circuit due to it's high reactance)

This open circuit is same as there are no capacitors that is why we neglect interelectrode capacitor at low frequency

what is Brackhausen criteria?

 what is brackhausen criteria to oscillate the oscillator?

It states that, if  A is gain of amplifier without feedback and β is the amplifier factor then to have a steady state oscillation in circuit for the frequency for which have

1.Loop gain is unity ( )

2.Total phase shift introduced in the circuit (or) phase shift around loop is zero or integral multiple of 2π