Ham Radio General Class Practice Test

What is an effect of inter-turn capacitance in an inductor?

1. The magnetic field may become inverted

2. The inductor may become self resonant at some frequencies

3. The permeability will increase

4. The voltage rating may be exceeded

The correct answer is: The inductor may become self resonant at some frequencies

Inter-turn capacitance in an inductor refers to the capacitance that occurs between the closely spaced turns of the wire in the coil. This capacitance can have significant effects on the behavior of the inductor, particularly at higher frequencies. When the frequency increases, the reactance of the inductance rises, but the reactance of capacitance decreases. If the frequency becomes high enough, the inductor can start to resonate, creating a condition where the inductive reactance and capacitive reactance are equal. This phenomenon is known as self-resonance. At this resonant frequency, the inductor may no longer behave like a typical inductor; instead, it will start to exhibit characteristics of a resonant circuit, which can lead to unintended signal amplification or distortion. This is why the correct answer highlights that the inductor may become self-resonant at certain frequencies, which is a consequence of the inter-turn capacitance. The other options relate to fundamental properties of inductors but do not directly connect to the role that inter-turn capacitance plays in influencing the behavior of an inductor under varying frequency conditions. For instance, while magnetic field inversion and changes in permeability might be considerations for other scenarios, they are not directly linked to inter-turn