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damosuz
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Why don't we just connect a sine wave generator in series with a DMM and the coil, set the amplitude Δv0 to a given value on a scope, measure the RMS current I on the DMM and use Z = 0.707Δv0/I?
damosuz said:Yes, I know that Z depends on f, L and the resistance R of the coil. But you could measure Z by the method I described above and then find L (let's say) from the measured values of f and R. But nobody seems to do it like that.
meBigGuy said:Of course that only works if you care about Z in a frequency range that your DMM can deal with, and you don't care about DMM resistance or lead inductance. The DMM resistance could be more than your inductor. You should try it in the lab with a few inductors and see what the practical issues really are.
If you can neglect loses, yes. Otherwise, you need to now Rω or φ or P. There could be also other issues like parasitic capacities if you go too high with frequency.damosuz said:So if I understand well the IZ I=Vrms/Irms method will only allow me to determine L accurately for a nonferromagnetic coil and low frequencies.
Now, would the IZ I=Vrms/Irms method allow me to determine the capacitance of a capacitor from Z = 1/2πfC, using the frequency I like ?
Most likely, such frequency is too high for yor DMM to be accurate enough. Trust your scope.damosuz said:One last question: with the coil connected directly to the generator, I noticed that for high frequencies a DMM measured a RMS voltage that was less than the amplitude (as measured on the scope) divided by √2. Do you have an explanation for that?
damosuz said:Thank you! How can you measure P?...
damosuz said:Thank you! How can you measure P?
One last question: with the coil connected directly to the generator, I noticed that for high frequencies a DMM measured a RMS voltage that was less than the amplitude (as measured on the scope) divided by √2. Do you have an explanation for that?
Impedance is the measure of opposition to the flow of alternating current (AC) in a circuit. It is represented by the symbol Z and is measured in ohms.
To measure the impedance of a coil, you will need a multimeter or an impedance meter. Connect the meter to the coil and set it to the appropriate AC measurement range. Then, measure the voltage across the coil and the current passing through it. The impedance can be calculated using the formula Z = V/I, where V is the voltage and I is the current.
The factors that affect the impedance of a coil include the number of turns in the coil, the material of the wire, the diameter of the wire, the type of core used, and the frequency of the AC current passing through the coil.
Measuring the impedance of a coil is important for understanding its performance in an electrical circuit. It can help determine the efficiency of the coil, the amount of power it can handle, and how it will interact with other components in the circuit.
The measurement of coil impedance is important in various fields such as electrical engineering, physics, and telecommunications. It is used in the design and testing of electronic devices, in the analysis of power systems, and in the development of antennas and wireless communication systems.