🔍 Key Concepts

• Typical failure symptoms of vacuum tubes in radio transmitters (filament, plate, and gas issues) • Relationship between plate current and tube health (too low vs. too high) • How internal arcing and overheating appear and what they indicate

💭 Think About

• For each option, ask: does this describe a realistic and distinct symptom of a bad tube or is it unrelated? • Think about what happens if the filament fails, if gas gets into the tube, and if the tube draws abnormal plate current. • Consider whether defective tubes can fail in only one way or in several different, observable ways.

✅ Before You Answer

• For each listed symptom, ask if it would reduce transmitter performance or damage the tube or circuitry. • Check whether both too little plate current and too much plate current can indicate different kinds of tube defects. • Verify whether internal gas, arcing, overheating, and loss of emission are all recognized tube-failure modes.