1) As a dynamic energy storage device.I'm just wondering what an inductor is useful for?
Counter voltage is always present when the coil current is changing. During that time it is storing or releasing energy in a magnetic field. The value of the counter voltage is directly proportional to the rate of current change. During the time that no current change is present, the coil sustains a steady magnetic field where energy is stored. This field always present when current exists.And what about the counter EMF?
No, both store energy. Capacitors store energy in a electric field, and inductors store energy in a magnetic field. Voltage and current by themselves are not energy. Voltage sustains a electric field, and current sustains a magnetic field.Bill; Sorry for being such a newbie but is it capacitors that store voltage and inductors that store current?
Yes, inductive impedance is proportional to the frequency and also to the value of the inductance.Also, is it correct that inductor's impedence to the circuit is determined by the frequency of the signal?
Inductors only oppose current in AC and transient circuits. Inductors and resistors oppose current by two different mechanisms. Inductors generate a back voltage which opposes current changes. During that time, energy is stored during one-half cycle and released during the next half-cycle. No energy is expended. Resistors reduce voltage by dissipating energy. Since voltage is the energy density of the charge, pushing a charge through a resistor will reduce the amount of energy the charges contain, and thereby the energy density of the charge. So the voltage will decrease because the energy is reduced and dissipated as heat. Of course this works with resistors for DC too. In summary, inductors and capacitors reduce current by back-voltage, and resistors reduce current by dissipating energy.Also (sorry!), why would you use an inductor to oppose current instead of just using a resistor?
A common application for this is florescent ballasts. A resistor generates heat (sometimes lots of heat) resisting current flow. This is pure waste. A coil does it differently, no heat involved, which is why florescent bulbs are generally so efficient.Also (sorry!), why would you use an inductor to oppose current instead of just using a resistor?
So the inductive impedance is proportional to the frequency and the value of the inductor, but what about the magnitude of the signal? I would think a larger signal would mean more impedance since the change of current in the postive and negative cycles of an AC signal would be greater. Or does the magnitude not make a difference, only the frequency and value of the inductor?Quote:
Yes, inductive impedance is proportional to the frequency and also to the value of the inductance.
Only the frequency and value of the inductor. You should be able to discern that easily by examinining the formula for inductive reactance.. ..Or does the magnitude not make a difference, Or does the magnitude not make a difference, only the frequency and value of the inductor?
No, inductive reactance is part of the impedance of the coil. The resistance of the coil from its wire is usually minimal compared to the inductive reactance. Read up on impedance and reactance relate to each other, and review what I posted before in this thread.And (last question), is inductive reactance just another name for the resistance a inductor provides to the circuit?