Phy TAS

measure B field with search coil:
1) 個方向未必 perpendicular
2) background varying B-field, say from nearby ac current.
3) Drop of emf in measurement due to current flow in coil.
inductor:
The inductor may not be "pure", meaning that it has certain resistance.
rectification of a c signal
1) The capacitor may allow some of the dc components to pass through, known as "leakage current".
2) The inductor may allow some of the ac components to pass through, since it has only a "high" but not "infinite" reactance to ac.
study phrase diff b/w V and I in RC and LR circuit
Same as before: Real inductor has some resistance value and real capacitor has "low" but not "zero" reactance towards ac.