🔍 Key Concepts

• Relationship between plate current and electron emission in vacuum tubes or thermionic devices • Meaning of saturation in an electrical or electronic context • Difference between conditions that limit current at the cathode/filament versus at the plate (anode)

💭 Think About

• Ask yourself: when current can no longer increase because all emitted electrons are already being collected, is that limitation happening at the plate side or at the electron emission side? • Which term (plate, electron, filament) correctly describes the point where increasing plate voltage no longer increases plate current at a fixed cathode temperature? • Think about which part of the device is "saturated" when the available emitted electrons just match the current flowing through the circuit.

✅ Before You Answer

• Be clear on what saturation current means in vacuum tube theory • Distinguish between saturation caused by limited emission from the cathode versus limitations at the plate • Verify that the chosen term correctly ties the saturation condition to the location (plate vs cathode/filament) where the limiting factor occurs.