FCC E5D - 电学与电路原理

#E5D01🔗

What is the result of conductor skin effect?

导体趋肤效应的结果是什么？

Resistance increases as frequency increases because RF current flows closer to the surface

由于射频电流流向更靠近表面，因此电阻随着频率的增加而增加

✓ 正确答案

Resistance decreases as frequency increases because electron mobility increases

由于电子迁移率增加，电阻随着频率增加而减小

Resistance increases as temperature increases because of the change in thermal coefficient

由于热系数的变化，电阻随着温度的升高而增加

Resistance decreases as temperature increases because of the change in thermal coefficient

由于热系数的变化，电阻随着温度升高而降低

#E5D02🔗

Why is it important to keep lead lengths short for components used in circuits for VHF and above?

为什么对于 VHF 及以上电路中使用的元件来说，保持较短的引线长度很重要？

To increase the thermal time constant

增加热时间常数

To minimize inductive reactance

最大限度地减少感抗

✓ 正确答案

To maintain component lifetime

维持元件的使用寿命

All these choices are correct

所有这些选项都是正确的

#E5D03🔗

What is the phase relationship between current and voltage for reactive power?

无功功率的电流和电压之间的相位关系是什么？

They are out of phase

它们异相

They are in phase

他们同相

They are 90 degrees out of phase

它们的相位相差 90 度

✓ 正确答案

They are 45 degrees out of phase

它们的相位相差 45 度

#E5D04🔗

Why are short connections used at microwave frequencies?

为什么在微波频率下使用短连接？

To increase neutralizing resistance

增加中和电阻

To reduce phase shift along the connection

减少沿连接的相移

✓ 正确答案

To increase compensating capacitance

增加补偿电容

To reduce noise figure

降低噪声系数

#E5D05🔗

What parasitic characteristic causes electrolytic capacitors to be unsuitable for use at RF?

哪些寄生特性导致电解电容器不适合在射频下使用？

Skin effect

趋肤效应

Shunt capacitance

并联电容

Inductance

电感

✓ 正确答案

Dielectric leakage

漏电

#E5D06🔗

What parasitic characteristic creates an inductor’s self-resonance?

什么寄生特性会产生电感器的自谐振？

Skin effect

趋肤效应

Dielectric loss

介电损耗

Coupling

联轴器

Inter - turn capacitance

匝间电容

✓ 正确答案

#E5D07🔗

What combines to create the self-resonance of a component?

是什么结合起来产生元件的自谐振？

The component’s resistance and reactance

元件的电阻和电抗

The component’s nominal and parasitic reactance

元件的标称电抗和寄生电抗

✓ 正确答案

The component’s inductance and capacitance

元件的电感和电容

The component’s electrical length and impedance

元件的电气长度和阻抗

#E5D08🔗

What is the primary cause of loss in film capacitors at RF?

薄膜电容器在射频下损耗的主要原因是什么？

Inductance

电感

Dielectric loss

介电损耗

Self-discharge

自放电

Skin effect

趋肤效应

✓ 正确答案

#E5D09🔗

What happens to reactive power in ideal inductors and capacitors?

理想电感器和电容器中的无功功率会怎样？

It is dissipated as heat in the circuit

它在电路中以热量形式耗散

Energy is stored in magnetic or electric fields, but power is not dissipated

能量存储在磁场或电场中，但功率不会耗散

✓ 正确答案

It is canceled by Coulomb forces in the capacitor and inductor

它被电容器和电感器中的库仑力抵消

It is dissipated in the formation of inductive and capacitive fields

它在电感和电容场的形成中被消耗掉

#E5D10🔗

As a conductor’s diameter increases, what is the effect on its electrical length?

随着导体直径的增加，对其电气长度有何影响？

Thickness has no effect on electrical length

厚度对电气长度没有影响

It varies randomly

它随机变化

It decreases

它减少了

It increases

它增加了

✓ 正确答案

#E5D11🔗

How much real power is consumed in a circuit consisting of a 100-ohm resistor in series with a 100-ohm inductive reactance drawing 1 ampere?

由 100 欧姆电阻与 100 欧姆感抗串联组成的电路消耗 1 安培的实际功率是多少？

70.7 watts

70.7瓦

100 watts

100瓦

✓ 正确答案

141.4 watts

141.4瓦

200 watts

200瓦

#E5D12🔗

What is reactive power?

什么是无功功率？

Power consumed in circuit Q

电路Q消耗的功率

Power consumed by an inductor’s wire resistance

电感器的线电阻消耗的功率

The power consumed in inductors and capacitors

电感器和电容器消耗的功率

Wattless , nonproductive power

无功、非生产性电力

✓ 正确答案

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FCC E5D - 电学与电路原理

小节 E5D：电学与电路原理