🔍 Key Concepts

• Impedance vs resistance for AC and DC in an inductor • What a choke coil is used for in radio or power circuits • Meaning of high Q in RF (radio frequency) coils

💭 Think About

• Think about how an inductor behaves for DC current versus AC current—does it block one more than the other? • Why would a designer choose a choke coil in an RF or power supply filter? What properties are they taking advantage of? • If a coil has a high Q (low losses), how does that relate to its effectiveness in passing or rejecting certain kinds of currents?

✅ Before You Answer

• Be clear on the difference between impedance to AC and resistance to DC in an inductor. • Recall that Q (quality factor) describes how lossy (or efficient) a resonant coil is at RF. • Verify whether a practical choke coil is expected to have all of the listed properties or only some of them.