Measuring Inductance in an LR Circuit with AC

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Discussion Overview

The discussion revolves around measuring inductance in an LR circuit using alternating current (AC) at different frequencies. Participants explore the implications of frequency choice on measurement accuracy and the relationship between reactance and resistance in the circuit.

Discussion Character

  • Technical explanation, Conceptual clarification, Debate/contested

Main Points Raised

  • One participant notes that the inductance of the cable is approximately 10^-7 and questions why 1 MHz is preferable for measurement compared to 100 kHz.
  • Another participant suggests that clarity in measurement methods, particularly regarding phase shift between current and voltage, is important when resistance and reactance are comparable.
  • A later reply emphasizes that the impedance of an inductor increases with frequency, arguing that the low inductance value supports the choice of 1 MHz for better measurement output.

Areas of Agreement / Disagreement

Participants express differing views on the measurement methods and the implications of frequency choice, indicating that the discussion remains unresolved with multiple perspectives presented.

Contextual Notes

Details regarding the specific measurement method and any assumptions about circuit conditions are not fully provided, which may affect the interpretation of frequency choice and its impact on measurement accuracy.

momomo_mo
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In an LR circuit with alternating current , it is know that the inductance of the cable is of the order 10^-7 . With a 2 ohm resistor ,the circuit is used to measure inductance.There are 2 frequencies , 100kHZ and 1M Hz,that can be chosen for the measurement .
So whyI MHz is better . I know that it is because order of magnitude of reactance is comparable to that of resistor.But why is it better ??

Thanks!
 
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It would be clearer if you provided details of the measurement method. If you are looking at the phase shift between the current and voltage, then it is easiest to measure when the resistance and reactance are comparable.
 
I see your point.Thanks
 
The impedance of an inductant depends on the frequency, the higher the frequency, the larger the impedance. In your case, the inductance of the cable is of the order 10^-7 which is quite low, so we should use the 1MHz frequency for measuring to have better output.
 

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