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Why must the instantaneous current wave be exact 90 degree out-of phase with the applied voltage waveform across an ideal inductor?
Wiki User
∙ 12y ago
Because the voltage induced is proportional to the rate of change of current, and the maximum rate of change of current occurs at the point where the current waveform is 'steepest' -i.e. as it passes through zero. So, as the current passes through zero, the corresponding value of induced voltage is maximum, which means the voltage and current waveforms are displaced by a quarter of the wavelength, or 90 degrees.
Wiki User
∙ 12y ago
Wiki User
∙ 12y agoBecause the voltage induced is proportional to the rate of change of current, and the maximum rate of change of current occurs at the point where the current waveform is 'steepest' -i.e. as it passes through zero. So, as the current passes through zero, the corresponding value of induced voltage is maximum, which means the voltage and current waveforms are displaced by a quarter of the wavelength, or 90 degrees.
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1 If the voltage applied across a capacitance is triangular in waveform then the waveform of the current is?
rectangular
Is square wave inverter harmful to tvs?
The square wave inverter can be harmful to any device that has an AC to DC power supply, which almost every device does, because the slope of the incoming waveform is higher than usual and the interception point of the ripple waveform with the incoming waveform when the diode turns on can can high current transients in the diode. The can be minimized somewhat by using a series inductor to filter the high current transients.
What component limits current in a circuit?
A resistor or an inductor. The inductor limits transient current, not steady state current.
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.
What is working principle of inductor?
A changing current through an inductor induces a voltage into the inductor, the direction of which always opposes the change in that current.So, in a d.c. circuit, an inductor will oppose (not prevent) any rise or fall in current, although the magnitude of that current will be determined by the resistance of that inductor, not by its inductance.In an a.c. circuit, because the current is continuously changing both in magnitude and in direction, it acts to continuously oppose the current due to its inductive reactance. Inductive reactance is proportional to the inductance of the inductor and the frequency of the supply. The vector sum of the inductive reactance of the inductor and the resistance of the inductor, is termed the impedance of the inductor. Inductive reactance, resistance, and impedance are each measured in ohms.
Why voltage leads current in a inductor?
Eli the ice man. Voltage (E) before Current (I) in a coil (inductor)(L) Current (I) before Voltage (E) in a Cap. (C) Got it?
1 If the voltage applied across a capacitance is triangular in waveform then the waveform of the current is?
rectangular
Suppose no energy given to inductor and a decreasing current is applied to it. emf will be produced and energy is given by it.so i think energy is not stored in inductor. it is its own property?
How do you propose to connect a decreasing current to the inductor ? The initial current through the inductor is zero, and you want to connect it to a current which is not zero and decreasing. At the instant you make the connection, the inductor current is zero, and it must rise to the non-zero value where you want it to begin decreasing. The current in the inductor cannot change from zero to something in zero time. As it rises from zero to the initial value, guess what . . . the inductor is storing energy in its magnetic field, while producing the usual voltage equal to [ L di/dt ].
Is square wave inverter harmful to tvs?
The square wave inverter can be harmful to any device that has an AC to DC power supply, which almost every device does, because the slope of the incoming waveform is higher than usual and the interception point of the ripple waveform with the incoming waveform when the diode turns on can can high current transients in the diode. The can be minimized somewhat by using a series inductor to filter the high current transients.
What component limits current in a circuit?
A resistor or an inductor. The inductor limits transient current, not steady state current.
How current lags the voltage in inductor?
In a perfect inductor (one with no series internal resistance), the current lags the voltage by 90 degrees. If the inductor has series internal resistance, then the current will lag the voltage by less than 90 degrees - the more the resistance in series with the inductor, the smaller the angle. The tangent of the angle can be found from the ratio of the inductive reactance of the inductor to the DC resistance of the inductor. That is, Tan (phase angle) = (2 x pi x frequency (Hz) x inductance (H)) divided by resistance (ohms) eg, a 1 henry, 100 ohm inductor on 60Hz would give: (2 x pi x 60 x 1) / 100 = 3.77; tan-1(3.77) gives 75 degrees lag of current behind voltage. The cosine of this angle gives the 'power factor' for the inductor - that is, the amount of useful energy dissipated in the inductor. Cos 75 is about 0.25 - so 25% of the energy actually does useful work (heat) - the rest of the energy (75%) is returned to the supply mains when the inductor discharges its magnetic field.
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.
Inductor works in direct current?
Yes, an inductor works with direct current. It is called an electromagnet. Of course, a practical electromagnet has series resistance, otherwise the current in the inductor would increase to the limit of the current/voltage source.
What is instantaneous power mean?
The product of the instantaneous voltage and the instantaneous current for a circuit or component.
What is working principle of inductor?
A changing current through an inductor induces a voltage into the inductor, the direction of which always opposes the change in that current.So, in a d.c. circuit, an inductor will oppose (not prevent) any rise or fall in current, although the magnitude of that current will be determined by the resistance of that inductor, not by its inductance.In an a.c. circuit, because the current is continuously changing both in magnitude and in direction, it acts to continuously oppose the current due to its inductive reactance. Inductive reactance is proportional to the inductance of the inductor and the frequency of the supply. The vector sum of the inductive reactance of the inductor and the resistance of the inductor, is termed the impedance of the inductor. Inductive reactance, resistance, and impedance are each measured in ohms.
Why does the ratio of the voltage to current in capacitor and inductor depend on frequence?
The ratio of voltage to current, or the impedance, of reactive elements such as capacitors and inductors depends on the frequency of the applied wave because they store energy, and the amount of energy they store is directly related to the frequency of the applied waveform. When a DC voltage is applied to a capacitor, the current through the capacitor initially will be large, and will decay down to zero as the capacitor charges. Also, the voltage across the capacitor will be small initially and will increase over time to be equal to the applied voltage. This behavior results in a varying impedance when an AC waveform is applied. At a very low frequency, the capacitor will charge up and discharge similarly to if a DC source was switched into the capacitor for a long period of time there would be a large voltage drop, and small current = high impedance). As the frequency increases, the capacitor will appear more like a DC source was initially switched into the capacitor (low voltage drop and high current = low impedance).
WHY does the ratio of the voltage to current in capacitor and inductor depend on frequency?
The ratio of voltage to current, or the impedance, of reactive elements such as capacitors and inductors depends on the frequency of the applied wave because they store energy, and the amount of energy they store is directly related to the frequency of the applied waveform. When a DC voltage is applied to a capacitor, the current through the capacitor initially will be large, and will decay down to zero as the capacitor charges. Also, the voltage across the capacitor will be small initially and will increase over time to be equal to the applied voltage. This behavior results in a varying impedance when an AC waveform is applied. At a very low frequency, the capacitor will charge up and discharge similarly to if a DC source was switched into the capacitor for a long period of time there would be a large voltage drop, and small current = high impedance). As the frequency increases, the capacitor will appear more like a DC source was initially switched into the capacitor (low voltage drop and high current = low impedance).
