Electronic and Communications Interview Questions - Part 9
What do you mean by zener breakdown and avalanche breakdown ?
Zener breakdown In Zener breakdown the electrostatic attraction between the negative electrons and a large positive voltage is so great that it pulls electrons out of their covalent bonds and away from their parent atoms. ie Electrons are transferred from the valence to the conduction band. In this situation the current can still be limited by the limited number of free electrons produced by the applied voltage so it is possible to cause Zener breakdown without damaging the semiconductor. Avalanche breakdown Avalanche breakdown occurs when the applied voltage is so large that electrons that are pulled from their covalent bonds are accelerated to great velocities. These electrons collide with the silicon atoms and knock off more electrons. These electrons are then also accelerated and subsequently collide with other atoms. Each collision produces more electrons which leads to more collisions etc. The current in the semiconductor rapidly increases and the material can quickly be destroyed.
What are the different types of filters ?
Low pass, high pass, band pass, band stop, resonant
What is sampling theorem ?
Sampling Theorem: A band limited signal can be reconstructed exactly if it is sampled at a rate atleast twice the maximum frequency component in it.
What is impulse response ?
Impulse response is the response of a system to a unit impulse at its input. The impulse response function is the inverse Laplace transform of the system transfer function H(s).
Explain the advantages and disadvantages of FIR filters compared to IIR counterparts.
IIR filters are recursive and FIR filters are non-recursive. Also FIR filters are linear phase and IIR filters are not. fir filter are highly stable. We can obtain linear phase in fir filter. rounding error is abscent in fir filter.
What are the flags in 8086 ?
Carry flag, Parity flag, Auxiliary carry flag, Zero flag, Overflow flag, Trace flag, Interrupt flag, Direction flag, and Sign flag.
What are the various interrupts in 8086 ?
Maskable interrupts, Non-Maskable interrupts
What is meant by Maskable interrupts ?
An interrupt that can be turned off by the programmer is known as Maskable interrupt.
Which interrupts are generally used for critical events ?
Non-Maskable interrupts are used in critical events Such as Power failure, Emergency, Shut off etc.