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Why cant you use the voltage across the inductor and the voltage across the lamp to find the supply voltage in a fluorescent fitting?
Wiki User
∙ 9y ago
Because the two voltages are out of phase, that means that individually they peak at different times in the AC cycle, so in general if they are measured separately their sum will exceed the supply voltage, possibly by up to 41%.
Wiki User
∙ 9y ago
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Why the voltage drop across inductance and voltage drop across capacitance is greater than source voltage in series resonance circuit?
The reason for the total voltage drops across the capacitance and inductance IN AN AC CIRCUIT has to do with the different phase angles of the voltages.First, current is the same value and same phase angle everywhere in a series circuit. But, voltage across a capacitor lags current by 90 degrees (capacitor current leads voltage). Next, voltage across a pure inductance leads current by 90 degrees (inductor current lags voltage).The rule that all voltages in a series circuit have to add to the supply voltage still applies, but in this case, the voltage drops are added VECTORALLY, not arithmetically. If you were to graph this addition, you would show any resistance voltage in phase with the current, the capacitor voltage at -90 degrees to the current and the inductor voltage at +90 degrees to the current, for a phase difference between them of 180 degrees, cancelling each other out.In a series resonant circuit, the impedances of the capacitor and inductor cancel each other. The only impedance to the flow of current is any resistance in the circuit. Since real-life inductors always have some resistance, at least there is always some resistance in a series resonant circuit.
What happens when a dc voltage is applied to an inductor?
The equation of an inductor is ...di/dt = V/L... meaning that the rate of change of current in amperes per second is proportional to voltage and inversely proportional to inductance in henries.If, for example, you connect a 200 millihenry inductor across a 12 volt battery, the current will increase at a rate of 60 amperes per second.Now, the question is, can the inductor, conductors, and/or battery handle that? The answer is no. Something is going to fail. The inductor will rather quickly look like a short circuit across the battery.This example does not take resistance into account. Practical inductors, conductors, and batteries have resistance, and that will place an upper limit on current but, still, this is not an appropriate way to connect an inductor to a battery.DO NOT TRY IT IN THE LAB - THERE IS RISK OF EXPLOSION.
In an AC circuit with only an inductor what will an increase in frequency do?
Inductor impedance is given by jwL, where w=2*pi*frequency. Therefore as the frequency increases the impedance of the inductor increases, causing a larger current flow and a larger power dissipation across the inductor
Why potential difference is same for each capacitive connected in parallel combination?
Because it is simple phenomenon of electricity everything(resistance,capacitor,inductor) connected in parallel holds the same voltage across the each parallel element.
How does the coil of wire wrap around the iron core works as a surge suppressor?
A coil of wire wrapped around an iron core forms an inductor. In AC systems, an inductor's impedance appears equivalent to j*w*L (j = i = imaginary number, w = omega = frequency in radians, L = inductance). A surge is inherently high frequency. Here's an example to help explain why this acts as a surge supressor: Say I have a 10mH surge supressing inductor. My device uses 1 amp of current at 120 volts, so its' resistance is 120 ohms. Under normal operation (60 Hz), the inductor's impedance appears as (j*2*pi*60*10/1,000) 3.8 ohms. Voltage to my device is ~120 volts, and voltage dropped (or "supressed") is (3.8 / (120 + 3.8) * 120 ) = 3.7 volts. My device is only seeing 116.3 volts with this inductor in place, but that's not enough of a dip to hurt its' operation. A power surge hits this device. This power surge is at a frequency of 50kHz, and a voltage of 80v (an overvoltage to my device of 120 + 80 = 200 volts). The impedance of the inductor "looks like" (j*pi*50,000*10/1,000) 3141 ohms, which is in series with my 120 ohm load. The surge voltage dropped across the inductor is (3141 / (3141+120) * 80) = 77 volts, so my device gets hit with ~3 surge volts (total voltage = 60 Hz voltage of 116.3 + 50kHz voltage of 3 = 119.3 volts).
What does the voltage across a inductor do?
voltage across inductor create a flux. because of variation current developes an opposite emf.
How will be the outputs across the inductor and resistor if you keep the frequency of the input signal very low?
For a low frequency source, the voltage across the inductor tends to zero because its impedance is proportionnal to source frequency, whereas the voltage across the resistor tends to the voltage source value.
Is there no induced voltage in an inductor unless the current is changing?
In an ideal inductor, no, there is no voltage induced across an inductor unless the current in the inductor is changing. However, since there are no ideal inductors nor power supplies, eventually an inductor will draw a constant current, i.e. the limit of the power supply; and, since no inductor has zero ohms at equilibrium, that current will translate to voltage.
Why alternating current induce voltage across an inductor?
due to change in flux
Does inductor allow ac to pass through it?
Yes, with some difficulty. You can think of an inductor as a kind of "AC resistor"in a way. The higher the frequency of the AC, the more difficulty it has passingthrough the inductor.If you apply AC voltage across an inductor, whereV = voltage of the ACf = frequency of the ACL = inductance of the inductor,then the AC current through the inductor isI = V/2 pi f L
What is principle of fluorescent tube light how choke gives transient voltage across tube at the time of starting?
11000
What is the relationship of current through the resistor and inductor in the LR parallel circuit?
When they are in parallel the same voltage appear across both. The resistor carries a current of V/R, the inductor carries a current of V/(jwL). So the current in the inductor is 90 degrees behind in its phase.
What happens when current flows through inductor?
When current flows through an inductor, a magnetic field is created. That's the simple explanation. More formally, an inductor is a magnetic device that reactively resists a change in current by presenting a voltage backwards towards the source. The equation for an inductor is ... di/dt = v/L ... which means the the rate of change in current in amperes per second is proportional to voltage in volts and inversely proportional to inductance in henrys. Theoretically, this means that, if you place a constant voltage across an inductor, current will linearly increase without bounds to infinity. Practically, this will be limited by resistance and current capacity.
How an electrical choke generat high energy?
A choke or inductor does not generate energy by itself but it can generate high voltages. The voltage across an inductor is equal to the inductance in Henrys times the rate of change of current in amps per second. So if an inductor is wired in series with a battery, then when one of the wires is disconnected the current dops quickly generating a high voltage which causes a spark. This principle is used to generate the high voltage for a spark plug in a car engine.
Why there's high voltage at series rlc resonant frequency?
With a series RLC circuit the same current goes through all three components. The reactance of the capacitor and inductor are equal and opposite at the resonant frequency, so they cancel out and the supply voltage appears across the resistor. This means that the current is at its maximum, but that current, flowing through the inductor and the capacitor, produces a voltage across each that is equal to the current times the reactance. The voltage magnification is the 'Q factor', equal to the reactance divided by the resistance.
What happens in series lcr circuit?
in a series lcr ckt., wen d voltage across inductor Vl is > dan voltage across capacitor Vc, d voltage leads the current by an angle phi... n wen Vc > Vl d current leads the voltage by an angle phi... resonance occurs wen d reactance of inductor Xl = reactance offered by capacitor Xc... n hence at resonance, current through the circuit is max n reactence of ckt is minimum...
Why the voltage drop across inductance and voltage drop across capacitance is greater than source voltage in series resonance circuit?
The reason for the total voltage drops across the capacitance and inductance IN AN AC CIRCUIT has to do with the different phase angles of the voltages.First, current is the same value and same phase angle everywhere in a series circuit. But, voltage across a capacitor lags current by 90 degrees (capacitor current leads voltage). Next, voltage across a pure inductance leads current by 90 degrees (inductor current lags voltage).The rule that all voltages in a series circuit have to add to the supply voltage still applies, but in this case, the voltage drops are added VECTORALLY, not arithmetically. If you were to graph this addition, you would show any resistance voltage in phase with the current, the capacitor voltage at -90 degrees to the current and the inductor voltage at +90 degrees to the current, for a phase difference between them of 180 degrees, cancelling each other out.In a series resonant circuit, the impedances of the capacitor and inductor cancel each other. The only impedance to the flow of current is any resistance in the circuit. Since real-life inductors always have some resistance, at least there is always some resistance in a series resonant circuit.
