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we know that frequency and time period are inversely proportional so as frequency decreases time period increases resulting in larger current flow thus increasing the dissipation.
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Electric power is transferred over large distances at very high voltages Explain how the high voltage reduces power losses in transmission lines?
The conductor used to transmit power has a specific resistance at the given power frequency. Power transmitted is equivalent to I^2 * R, so as the current increases, the power loss from the conductor also increases. To maximize efficiency, power is converted to very high voltages, which decreases the current, which minimizes the power lost in transmission.AnswerThe primary reason for using high voltage transmission lines is because, for a given load, the higher the voltage, the lower the load current. Low voltages would require cables of enormous cross-sectional area making transmission impossible, whereas high voltages allow the use of manageable-sized conductors. A secondary reason is the corresponding reduction in line losses -as described above.
How do vfd's change the AC to dc current and back into AC?
Variable frequency drives use a rectifier to "chop off" the top part of the ac wave, then use capacitors to "fill in" the gaps in the voltage, making a "near dc" power. They use IGBTs, a fancy term for a high speed, high current transistor, or electronic switch, to pulse the "near dc" power out to the motor, in a pattern that appears like ac to the motor.
Why a coil of wire placaed in series circuit allows low frequency current but not high frequency current to pass?
The opposition to an alternating current offered by a coil, or inductor, is called impedance (symbol Z, measured in ohms) which, in turn, is made up of two components: resistance (symbol R) and inductive reactance (symbol XL). These three quantities are related as follows: Z2 = R2 + XL2.The resistance of an inductor is a fixed value which depends upon the length of the coil's wire, the cross-sectional area of the wire, and the resistivity of the material from which the wire is made.The inductive reactance of an inductor, on the other hand is directly proportional to the frequency of the supply. So, at high frequencies, an inductor's inductive reactance is very much higher than at low frequencies.So, at high frequencies, the impedance of the inductor is higher because its inductive reactance is higher.The current flowing through a coil is, by Ohm's Law: I = V / Z. So, at high frequencies, the inductor's impedance will be much higher than at low frequencies, which means that a very much smaller current will flow when the frequency is high compare to when the frequency is low.
What is a rectifier assembly?
A "Rectifier" is an electrical component that changes AC current to DC current by blocking current in one direction. High power rectifiers may be "assembled" from multiple individual component rectifiers to handle higher power or larger voltages.
Which transistor is used for high speed power application?
In transistor the heat is created during transition stage means from cutoff to saturation and reverse, so if transistor used for high frequency application power loss can be minimized. The heat produced during switching is actually power loss.
What is the key difference between old computers and the present day computers?
vacuum tubes, large sized, high power dissipation, high voltagestransistors, medium sized, medium power dissipation, low voltagesintegrated circuits, small size, medium power dissipation, low voltagesmicroprocessors, very small size, low power dissipation, low voltages
What does a transmission system at a radio station use to convert a direct current into a high frequency alternating current?
a high power, often class C amplifier.
Explain why diodes melt?
Diodes, like many other electronic/electrical components, will melt if the temperature is high enough. This would occur if the power dissipation were too high because the current was too high.
How do you reduce the Power dissipation?
Answer for mechanical systems:Use oil or grease to reduce friction!Answer for electrical systems:Making the voltage as high as possible is a good way to reduce power loss.ExplanationThe voltage drop along a conductor is proportional to the resistance and to the current carried. (V=IxR) So, for a given quantity of Power (W=VxI), if the voltage is made as high as possible there will be less current flowing and therefore less power loss.
High frequency is direct or indirect current?
-- There's no such thing as 'indirect' current.-- Direct current has no frequency. As soon as you mention 'frequency',you're talking about alternating current.
Which mode of transmission would result in less energy loss high current and low voltage or low current and high voltage Explain your reason?
low current high voltage power dissipation in power line = I2R the resistance of the power line is hard to reduce, especially when it is a long transmission line. but reducing the current through the line reduces losses as the square, a dramatic savings. reducing voltage would have no effect and would dramatically increase losses due to increase in current to try to deliver same power.
Why shouldn't totem-pole outputs be wire anded?
Totem pole TTL has the advantage of high speed and low power dissipation but itsdisadvantage is that it cannot be wired ANDed because of current spikes generation.
Why an ammeter is likely to burn out if connected in parallel combination?
ameter has a low resistance so if it is placed in parallel with the load then it will experiance voltage as much as the load and according to equation power=v2/r the power will be very high as high v or low r both favors for a high power dissipation . but on a series combination most of the voltage drop will be on load the ameter will not have a high power dissipation
Can hertz kill?
The meaning of Hertz is a unit of frequency in SI; a high frequency electrical current can kill.
What is the difference between TTL and CMOS interms of fan infan outlogic levelspropagation delay?
The power dissipation of CMOS devices is around 100 times lower than the value of power dissipation for TTL. This makes CMOS more suitable for devices to run on battery power and devices allows like mobile phones to have a longer batter life. CMOS devices only use power when switching from one state to the other state (high to low, or low to high) so on they need power for less of the time than TTL devices which use current and dissipate power all the time that they have a power supply.
Power is transmitted at high voltages because the corresponding current in the wires is?
If you transmit at high voltage, you can send the same power at low current (P=VI), this is good because high current, means that you have high resistance and then you lose power to heat.
How do you convert low frequency to high frequency with a circuit?
You typically create a DC power supply from the low frequency, and use that to run a high frequency oscillator and amplifier. If there needs to be a relationship between frequency in and frequency out, often there is a divider running on the high frequency side in combination with a phase locked loop synching up to the low frequency side.
