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In a normal AGC, even the unwanted signals gets amplified, But u dont want that to happen, so until the Input Signal strength reaches a threshold, the AGC feedback signal is not applied to the amplifier biasing circuit..
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What is vector impedance meter explain with circuit diagram?
A vector impedance meter is used to measure impedance and phase angle, this is done by calculating voltage and current through an impedance and then calculating Z and phase angle with that, now there are two modes for operation i.e constant current mode and constant voltage mode. CONSTANT CURRENT MODE construction = first of all there is a wien bridge oscillator(w) to choose frequency then an AGC amplifier(a) to regulate current then a z switch control(zs) which regulates gain of AGC amplifer, feedback to AGC amplifier is done by an dc differential amplifier(dc) dc | | | w--------->a--------->z now there is an ac differential amplifier too(ac) which gets one input from the z switch and one from the unknown impedance(imp), and there is a transconductance amplifier too which gets one of his input from the unknown impedance dc<------------------------------------------- | | | | | | w--------->a--------->z----------->ac-------------|------------> z meter | | | | | | _____| | | | | | | | | | | | imp | | | | | |________|___>rt___>| working---> in constant current mode we have to maintain constant current through impedance so current is made to come to unknown impedance from z switch, then that current goes through trans-resistance amplifier, which converts that current to a voltage that is sent to a dc differential amplifier and is compared with a reference voltage in dc differential amplifier then the difference between voltages is amplified and sent to AGC amplifier, so AGC together with z switch this way maintains constant current through unknown impedance, now for calculation z-magnitude, ac differential amplifier gets input from unknown impedance and z switch, so difference is amplified and sent to a band pass filter which filters out then the filtered signal is sent to a z-magnitude meter which is calibrated to read z directly.
How a fuse can provide time delayed protection for normal overload and high speed protection for short circuit?
There are two sections of the fuse; a straight wire section that provides quick acting response to short circuit conditions, and a coiled spring section with a soldered lump with thermal mass that provides time delay for normal overload. When inspecting a blown fuse, you can tell if it was a short or an overload by looking at where the blowout occurred.
Problems relating to load shedding?
Main sufferers: Students, patients in hospitals, industry Students: Cant study as there is no light in their home and so if there is an exam of him next day he cant do well in that exam. Patients in hospitals: May suffocate as the light and fans wont function. Operations of many serious patients get delayed. Industries: They get paralysed as there is no electricity. Thus they cannot produce enough and thus this economically hampers a country Foods in refrigerators get rotten. People become victims of pickpocekting and hijacking. (Almost all of the things that I have written is by taking idea from a book)
Why is it important to handle components properly in a computer?
Improper handling can completely destroy (or severely damage, causing a delayed failure) many electronics components, without the person handling them becoming aware that anything had even happened at the time the part was destroyed (or severely damaged).
What is Power systems protection?
Primary and back-up protectionThe reliability of a power system has been discussed in earlier sections. Many factors may cause protec­tion failure and there is always some possibility of a circuit breaker failure. For this reason, it is usual to supplement primary protection with other systems to 'back-up' the operation of the main system and ensure that nothing can prevent the clearance of a fault from the system.Back-up protection may be obtained automatically as an inherent feature of the main protection scheme, or separately by means of additional equip­ment.Time graded schemes such as over current or distance protection schemes are examples of those providing inherent back-up protection; the faulty section is normally isolated discriminatively by the time grading, but if the appropriate relay fails or the circuit breaker fails to trip, the next relay in the grading sequence will complete its operation and trip the associated circuit breaker, thereby inter­rupting the fault circuit one section further back. In this way complete back-up cover is obtained; one more section is isolated than is desirable but this is inevitable in the event of the failure of a circuit breaker.Where the system interconnection is more complex, the above operation will be repeated so that all parallel infeeds are tripped.If the power system is protected mainly by unit schemes, automatic back-up protection is not obtained, and it is then normal to supplement the main protection with time graded over current pro­tection, which will provide local back-up cover if the main protective relays have failed, and will trip further back in the event of circuit breaker failure.Such back-up protection is inherently slower than the main protection and, depending on the power system configuration, may be less discriminative. For the most important circuits the performance may not be good enough, even as a back-up protection, or, in some cases, not even possible, owing to the effect of multiple infeeds. In these cases duplicate high speed protective systems may be installed. These provide excellent mutual back-up cover against failure of the protective equipment, but either no remote back-up protection against circuit breaker failure or, at best, time delayed cover.Breaker fail protection can be obtained by checking that fault current ceases within a brief time interval from the operation of the main protection. If this does not occur, all other connections to the bus bar section are interrupted, the condition being necessarily treated as a bus bar fault. This provides the required back-up protection with the minimum of time delay, and confines the tripping operation to the one station, as compared with the alternative of tripping the remote ends of all the relevant circuits.The extent and type of back-up protection which is applied will naturally be related to the failure risks and relative economic importance of the system. For distribution systems where fault clearanceTimes are not critical, time delayed remote back-up protection is adequate but for EHV systems, where system stability is at risk unless a fault is cleared quickly, local back-up, as described above, should be chosen.Ideal back-up protection would be completely independent of the main protection. Current trans-formers, voltage transformers, auxiliary tripping relays, trip coils and D.C. supplies would be duplicated. This ideal is rarely attained in practice. The following compromises are typical:a. Separate current transformers (cores and secondary windings only) are used for each protec­tive system, as this involves little extra cost or accommodation compared with the use of common current transformers which would have to be larger because of the combined burden.b. Common voltage transformers are used because duplication would involve a considerable increase in cost, because of the voltage transformers them-selves, and also because of the increased accom­modation which would have to be provided. Since security of the VT output is vital, it is desirable that the supply to each protection should be separately fused and also continuously supervised by a relay which will give an alarm on failure of the supply and, where appropriate, prevent an unwanted operation of the protection.c. Trip supplies to the two protections should be separately fused. Duplication of tripping batteries and of tripping coils on circuit breakers is sometimes provided. Trip circuits should be continuously supervised.d. It is desirable that the main and back-up protections (or duplicate main protections) should operate on different principles, so that unusual events that may cause failure of the one will be less likely to affect the other.Previous Next
Types of Automatic gain control circuits?
2 types 1.simple AGC 2.delayed AGC
Why do you use a delayed AGC?
The disadvantage of automatic gain control, attenuating even the weak signal, is overcome by the use of delayed automatic gain control (dagc).
Difference between ABC and agc fuses?
ABC = Ceramic Body AGC = Glass Body
What does AGC stand for on a fuse?
AGC is a fuse type IE; the glass ones with the metal tips on the ends.
What does ACG mean on a fuse?
Are you sure you do not mean AGC? AGC stands for Automotive Glass Cartridge (Fuse). AGC fuses are fast acting fuses that will blown very quickly to protect components.
What is the difference between AGC and ABC fuses?
AGC fuses have glass body. ABC fuses have a ceramic body.
AGC is used in which of the stage?
Recievers
Do I use sfe or agc style fuses for my 1965 Impala?
Which style of fuse do I use for 1965 SS Impala, sfe or agc?
What complementary strand of dna would be produced by the strand of dna tcg ga?
AGCCT and in RNA sequencing it would be UGCCT
What is the AGC from Stargate SG-1?
It's a typo it should be SGC the A being so close to the S and presto-digit-tation AGC
Is AGC are used in oscillator or in receiver?
Yes, It is.
What is the difference between an AGS fuse and an AGC fuse?
The ags is an obsolete fuse no longer in production. It is nearly identical to the agc except it has a larger diameter
