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What is the dominant mode of propagation in microstrip line in low frequency approximation?
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∙ 12y ago
quasi-TEM
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∙ 12y ago
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Why the te0 mode is the dominant mode in rectangular waveguide?
Because it has the lowest cut-off frequency (highest cut off wavelength) for a>b o
How VVVF Drive works?
How Does a VSD (frequency converter, VFD) Work (part 1)?Induction motors, which are the workhorses of industry, rotate at a speed that is determined by the frequency of the supply voltage. Alternating current (AC) applied to the stator windings produces a magnetic field that rotates at synchronous speed. This speed may be calculated by dividing line frequency by the number of magnetic pole pairs in the motor winding.A four-pole motor, for example, has two pole pairs, and therefore the magnetic field will rotate 60 Hz / 2 = 30 revolutions per second, or 1800 rpm. The rotor of an induction motor will attempt to follow this rotating magnetic field, and, under load, the rotor speed "slips" slightly behind the rotating field. This small slip speed generates an induced current, and the resulting magnetic field in the rotor produces torque.Since an induction motor rotates near synchronous speed, the most effective and energy-efficient method to change the motor speed is to change the frequency of the applied voltage.Variable frequency drives (frequency changers) convert the fixed-frequency supply voltage to a continuously variable frequency, thereby allowing adjustable motor speed.A VSD (frequency converter, variable speed drive, variable frequency drive, VFD) converts 60 Hz power, for example, to a new frequency in two stages: the rectifier stage and the inverter stage. The conversion process of frequency changers incorporates three functions:1. Rectifier stage:A full-wave, solid-state rectifier converts three-phase 60 Hz power from a standard 208, 460, 575 or higher utility supply to either fixed or adjustable DC voltage. The system may include transformers if higher supply voltages are used. (to be continued)How Does a VSD (frequency converter, VFD) Work (part 2)?Continued from the previous article: How Does a VSD (frequency converter, VFD) Work (part 1), we explain the other 2 stages of the conversion process of frequency changers below.2. Inverter stage:Electronic switches - power transistors or thyristors - switch the rectified DC on and off, and produce a current or voltage waveform at the desired new frequency. The amount of distortion depends on the design of the inverter and filter.3. Control system:An electronic circuit receives feedback information from the driven motor and adjusts the output voltage or frequency to the selected values. Usually the output voltage is regulated to produce a constant ratio of voltage to frequency (V/Hz). Controllers may incorporate many complex control functions.Converting direct current (DC) to variable frequency alternating current (AC) is accomplished using an inverter.Most currently available inverters use pulse width modulation (PWM) because the output current waveform closely approximates a sine wave. Power semiconductors switch direct current (DC) voltage at high speed, producing a series of short-duration pulses of constant amplitude. Output voltage is varied by changing the width and polarity of the switched pulses. Output frequency is adjusted by changing the switching cycle time. The resulting current in an inductive motor simulates a sine wave of the desired output frequency. The high-speed switching of a pulse width modulation (PWM) inverter results in less waveform distortion and, therefore, lower harmonic losses.The availability of low-cost, high-speed switching power transistors has made pulse width modulation (PWM) the dominant inverter type.Tags: vsd frequency converter vfd ac drive variable speed drive variable frequency drive Written by :Ben | Category :AC Drive | Comments :0 | Trackback :0 | Read :305
What dominant color appears for an incandescent bulb?
The answer is a blue-green colour.
What is dominant poles of transfer function?
These are values which make the denominator equal zero, therefore the system described by the transfer function would be unstable near these values.
Why is diamond a good of heat like metals but a bad conductor of electricity unlike metals?
this is due to the fact that diamond has perfect lattice structure which helps it to conduct heat but due to the absence of free electrons it cannot conduct electricity. there are two modes to conduct heat :1) thraugh free electron transfer 2) thraugh lattice vibration .in diamond lattice vibration is dominant. for further study read conduction heat tranfer .
The Hardy-Weinberg principle is written as the equation p2 2pq q2 1. What does p represent?
The frequency of the homozygous dominant genotype.
What is the frequency value of the first dominant peak in the frequency response?
buat lab ke?haha
The Hardy-Weinberg formula and what each of the terms mean?
formula: p2 + 2pq + q2 = 1 p+q=1 p = dominant (A) allele frequency q = recessive (a) allele frequency q2 = homozygous recessive frequency p2 = homozygous dominant frequency 2pq = heterozygous frequency
What is the dominant mode of microstrip line?
The line will not support a true TEM wave; at non-zero frequencies, both the E and H fields will have longitudinal components (a hybrid mode).The longitudinal components are small however, and so the dominant mode is referred to as quasi-TEM. kuldeep jaimini
What does 2pq represent in hardy weinbergs equation?
the frequency of the heterozygous dominant genotype
What does the Hardy Weinberg equation p2 represent?
The frequency of the homozygous dominant genotype.
Dose a frequency trait help determine if the trait is dominant or recessive?
Because it has things
If there are 19 plants with rough seeds in a population of 100 what is the allele frequency for smooth seeds?
The frequency of dominant which is smooth seed early is 0.556 or 6%.
What is the answer for the Hardy Weinberg equation?
p2 + 2pq + q2 = 1 and p + q = 1p = frequency of the dominant allele in the populationq = frequency of the recessive allele in the populationp2 = percentage of homozygous dominant individualsq2 = percentage of homozygous recessive individuals2pq = percentage of heterozygous individuals
In a certain population the dominant phenotype of a certain trait occurs 91 of the time what is the frequency of the dominant allele?
p^2+2pq=.91-->q^2=.09-->q=.3-->p=.7-->p^2=.49 p^2+2pq+q^2=1.49+2pq+.09=12pq=.42 the number of AA alleles =140-->49*2 + 42*1=140the number of AA alleles=60-->42*1 + 9*2=60 So the frequency of the dominant allele is equal to the number of dominant alleles over the total number of alleles.Therefore 140/200=.7.7 is frequency of the dominant allele
What does the q represent in hardy-weinberg equation?
It depends on what you make p equal to. P is usually the frequency of the dominant allele, which makes q the frequency of the recessive allele, but they can be switched. As long as p is one frequency and q is the other, the formula will work. So if you have the dominant allele frequency (A) =.6 then the recessive allele frequency (a) =.4, because p+q=1 When you plug the frequencies into the hardy-weinberg equation p^2 +2(p)(q) + (q)^2 = 1 then you have (0.6)^2 + 2(0.4)(0.6) + (0.4)^2 = 1 (0.6)^2 = 0.36 which is the frequency of dominant homozygotes 2(0.4)(0.6)=0.48 which is the frequency of heterozygotes (0.)^2 = 0.16 which is the frequency of recessive homozygotes If you have a population of 100 people, these frequencies would mean that: 36 people would be AA 48 people would be Aa 16 people would be aa Which would mean that 36+48=84 people would exhibit the dominant trait and 16 people would show the recessive trait.
The Hardy-Weinberg principle is written as the equation p2 plus 2pq plus q2 1. What does p represent?
p represents the square root of the frequency of the homozygous genotype AA.
