141⟩ What is the use of excitation table in digital electronics?
Excitation table is required when we want to design a state machine from the truth table of any of the flip flops used.
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185 Electronics Engineering Questions And Answers
142⟩ What is the difference between latches and flip flop
Latche is a bistable circut which respons to change of logic levelas they occure.It has no external inputs.
Flip flop is a basic element of memory . it store a single bit.It has a multiple input.
143⟩ What is difference between a multiplexer and encoder? also What is the between demultiplexer and decoder?
Please share your answers.
144⟩ What is the frequency range of satellite communication?
Satellite mainly works in c band(4-8GHz) or KU band(12-18GHz) and these are mainly for the downlink.
145⟩ Suppose In market 4N27 is not easily available So Which OPTO ISOLATOR can I use at the place of this?
what is 4N27
146⟩ Tell me Is there any junction in conductor?
No there is no junction in conductor. because its not semi-conductor. only semi-conductor contains junction
147⟩ Please provide details of the following standards RS-23-C 802.3 X.25 802.11?
In Telecommunications , RS 232 C is a standard for serial binary data interconnection between a Data Terminal equipment and Data Circuit terminating equipment.
802.3 is a standard specification for Ethernet, a method of physical communication in a local area network (LAN), which is maintained by the Institute of Electrical and Electronics Engineers (IEEE).
X.25 is an International Telecommunication Union-Telecommunication Standardization Sector (ITU-T) protocol standard for WAN communications that defines how connections between user devices and network devices are established and maintained.
802.11 refers to a family of specifications developed by the IEEE for wireless LAN technology. 802.11 specifies an over-the-air interface between a wireless client and a base station or between two wireless clients.
148⟩ How to test on design and style in software?
We can use GUI testing techniques and we can use also use automation tool for stylish applications.
149⟩ Which of the following architectures is/are not suitable for realizing SIMD?1. vector processor2. array processor3. von neumann4. both array processor and von neumann
2. array processor
150⟩ Explain what are semiconductor devices?
there are three types of materials. they are conductor , semi conductor and insulator.
where the semi conductor lies between the other two. ie. controlled conduction is possible in semi conductor.
thats why it is preferred in electronic devices.
A PN junction is formed in all the three types of materials. but in semi consuctor the junction is very thin and easy to break it with the very low voltage.
151⟩ Explain how many type of resistor are there in diode?
They are two types one is forward resistance
1.Forward resistance
2.Reverse
resistance
1.Forward resistance
This is the resistance offered in forward bias condition of the diode.
It is calculated by with the help of graph for voltage and current characteristic.
2.Reverse resistance
This resistance is offered in the reverse bias condition of the diode. It is also calculated by the same method.
152⟩ What is the difference between Silicon Controlled Switch (SCS) and Gate Turn-off Switch (GTO)?
SCS is nothing but the switch (sillicon controlled switch SCR),but GTO is one of the turn off method in SCR.if any other answer for this question please forward me too the answer.
153⟩ Describe transducer EI pickups in instrumentation and control engineering?
Please share your answers.
154⟩ What are the differences between voltage and current controlled devices?
In any (electronic) device controlling parameter is current it is called current controlled device. eg bilpolar transistor- output current is a function of base current.
In any (electronic) device controlling parameter is voltage it is called voltage controlled device. eg Field effect transistor- output current is a function of gate voltage.
It depends on the inherent physical mechanism which defines the primary (independent) controlling parameter.
155⟩ Why the input resistance of an ideal OP-AMP is infinite and output resistance is zero?secondly, how can we measure these resistances(input and output) in case of an ideal OP-AMP and Real OP-AMP in the following conditions when1- load is not connected.2- load is connected.
Ideal OP-AMP is a power ful concept.
If one goes through the history of amplifying devices, it becomes clear that less it loads the previous stage, better the output signal. ie. it is a trend toward higher and higher input impedances.
Also it is better to maintain the signal level irrespective of the LOAD connected at the ouput. Lesser the output impedance, less the signal amplitude reduction when load is connected. ie. it is a trend toward lower and lower output impedances.
As ideal opamp is a concept , by virtue it has zero output impedance and infinite input impedance, and they are not physically measurable but has to be taken for granted for the use in theoritical analysis.
To measure input resistance, of non ideal opamp, connect a known source at the input and give a signal (within Specifications) through a current meter of sufficient precision. Input voltage by current gives the input impedance.
To measure input resistance, of non ideal opamp, connect a known source at the input and give a signal (within Specifications) through a current meter of sufficient precision. Input voltage by current gives the input impedance.
To measure output resistance, of non ideal opamp, connect a known source at the input such that the output does not saturate and connect a load (within Specifications ) through a current meter of sufficient precision and meaure the output voltage. Output voltage by current gives the output impedance.
Please refer application notes by device manufacturers freely availble in internet for more precise and practical solutions.
156⟩ Explain in wave guides TEM wave propagation is not exit, give the physical interpretation?
Please share your answers.
157⟩ Explain what is the Tri State of a Signal?
In digital ciruit, the gate output can be only high or low. In highstate the output source current at a minimum voltage, greater than ~2.8V if load(fan out ) is proper. In low state it will sink current at max output voltage less than ~0.8V. Some times it is derirable to have a state output both not high or low. with neither sinking or sourcing (with high output impedance). This is called tristate. Tristate output cannot change output condition of succeding logic gates, unless tristate is disabled.
158⟩ Tell me why 440 volts instead of 660 volts in 3 phases of supply system?
In single phase supply, 220V is voltage diff. between Line & neutral while, In 3 phase supply there are 3 supply lines phase shifted at 120deg from each other, so net voltage diff. (the phase resultant) between two phases in accordance with phase angle of 120deg is 440V.
However in 3 phase, 4 line systems having 1 neutral also, the voltage diff. between neutral and any of the phase is 220V...
159⟩ What is the difference between PLC and DCS control system?
Actually DCS stands for Distribute control system and PLC for Programmable logic controllers... Both are used for Industrial automation. each have their adv and dis adv.. shortly this is all marketing strategies , both do same function.....
160⟩ The number of columns in a state table for a sequential circuit with m flip-flops and n inputs is1. m + n 2. m + 2n3. 2m + n 4. 2m + 2n
Its 2m+2n because..
If there are m flip-flops, there should be 2m nodes. If there are n inputs, then each node will have 2n.
