🔍 Key Concepts

• Vacuum tube detector operation and how it converts RF (radio frequency) power into audio or DC power • The role of grid bias, grid input resistance, and plate circuit in detection/rectification • How rectification in any part of the tube circuit can indicate detector service

💭 Think About

• Think about what must happen inside a tube for it to act as a detector: does it need to rectify the signal, control current flow, or both? • Consider how bias near cutoff affects which half of the RF cycle conducts: does that resemble a detector action? • Ask yourself whether only one, or more than one, of the listed conditions can reasonably occur in a tube specifically arranged to detect and recover power from an RF signal.

✅ Before You Answer

• Verify how grid bias near cutoff affects conduction over a small part of the RF cycle and whether that produces rectification/detection • Check if high input grid resistance is typical in detector stages to avoid loading the tuned circuit and to allow signal development • Confirm that plate circuit rectification can also serve as a detection mechanism and whether multiple such indicators could all be present in a power detector stage